Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey

Active travel, Modal shift, LEZ, Intervention ALL Metrics - Views Downloads How to cite this article Mueller W, Carson FS, Copsey H and Loh M. Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.13891.2) NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article. Export Citation Sciwheel EndNote Ref. Manager Bibtex ProCite Sente Select a format first ▬ ✚ Research Article Revised Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations] William Mueller https://orcid.org/0000-0001-8712-736X 1, Fiona S. Carson1, Helena Copsey1, Miranda Loh1William Mueller https://orcid.org/0000-0001-8712-736X 1, Fiona S. Carson1, Helena Copsey1, Miranda Loh1 PUBLISHED 19 Jan 2026 Author details Author details 1 Institute of Occupational Medicine (IOM), Research Ave N, EH14 4AP, Edinburgh, UK William Mueller Roles: Conceptualization, Funding Acquisition, Methodology, Writing – Original Draft Preparation Roles: Conceptualization, Funding Acquisition, Methodology, Writing – Original Draft Preparation Fiona S. Carson Roles: Formal Analysis, Methodology, Writing – Review & Editing Roles: Formal Analysis, Methodology, Writing – Review & Editing Helena Copsey Roles: Project Administration, Writing – Review & Editing Roles: Project Administration, Writing – Review & Editing Miranda Loh Roles: Methodology, Writing – Review & Editing Roles: Methodology, Writing – Review & Editing OPEN PEER REVIEW REVIEWER STATUS Low Emission Zones (LEZs) aim to improve air quality and encourage sustainable travel in urban areas by issuing fines to non-compliant vehicles. This study investigated initial impacts on travel behaviour and perceptions following the enforcement of Edinburgh's LEZ from June 2024. We conducted an online cross-sectional survey focussing on commuting behaviour inside and outside the LEZ, as well as prior to and several months after enforcement. The survey targeted adults who worked or studied in Edinburgh or otherwise travelled to the LEZ area. We collected data on demographics, travel habits, and reasons for travel choices. To maximise response, we recruited participants via an online survey panel (‘panel survey’ [n=351]) and social media (‘community survey’ [n=260]), for which statistical analysis was stratified. Following LEZ enforcement, there was a clear differentiation in transport mode usage, with more people using the car alone for their commute outside the LEZ and more people using public transport inside the LEZ. Few respondents changed whether they accessed the LEZ area. Nevertheless, comparing inside to outside commuters, 70 (44%) versus 8 (10%) in the panel survey, and 41 (24%) versus 4 (9%) in the community survey, respectively, reported some change in the frequency, duration, or mode of transport following enforcement. Results suggested a small, but statistically significant, shift towards active travel and public transport within the LEZ, with a decrease in private vehicle use. Panel survey respondents tended to agree more than community respondents with the potential positive impacts of the LEZ. We found evidence that active travel and public transport use increased within the first few months after the Edinburgh LEZ was enforced. Future research with objective, quantitative data should confirm these findings and assess impacts over a longer time-period. This research involved an online survey of adults who worked or studied in, or travelled to, Edinburgh's Low Emission Zone (LEZ). The survey collected data on travel habits and reasons for travel choices. We also asked people’s opinions about potential impacts of the LEZ. We were interested in whether there were changes within several months after enforcement began in June 2024, which was when fees started to be charged for higher polluting cars. The results showed differences in how people travelled inside and outside the LEZ, as well as before and after enforcement. More people used cars outside the LEZ and used public transport inside the LEZ. Following enforcement, there was a small shift towards walking, cycling, and using public transport within the LEZ. This study showed that more people walked, cycled and used public transport in the several months following enforcement of the LEZ. Future studies should look at the LEZ and how people travel over a longer period. Active travel, Modal shift, LEZ, Intervention Corresponding Author(s) William Mueller ([email protected]) Grant information: This project is funded by the National Institute for Health and Care Research (NIHR) under its Public Health Research (PHR) Programme (Grant Reference Number NIHR167483). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Copyright: © 2026 Mueller W et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. How to cite: Mueller W, Carson FS, Copsey H and Loh M. Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.13891.2) First published: 14 Apr 2025, 5:33 (https://doi.org/10.3310/nihropenres.13891.1) Latest published: 19 Jan 2026, 5:33 (https://doi.org/10.3310/nihropenres.13891.2) The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The revised version of the manuscript incorporates amendments suggested by the reviewers. Additional discussion has been added relating to the Edinburgh Low Emission Zone (LEZ) and other factors that may have influenced travel behaviour during the study period. To enhance clarity, some of the original figures and tables have been condensed or removed in the revised version. Specifically, we have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. We have removed Figures 8 and 16, which had small sample sizes. More information is provided on the demographics of the survey respondents in comparison to the general population of Edinburgh. The revised version of the manuscript incorporates amendments suggested by the reviewers. Additional discussion has been added relating to the Edinburgh Low Emission Zone (LEZ) and other factors that may have influenced travel behaviour during the study period. To enhance clarity, some of the original figures and tables have been condensed or removed in the revised version. Specifically, we have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. We have removed Figures 8 and 16, which had small sample sizes. More information is provided on the demographics of the survey respondents in comparison to the general population of Edinburgh. Additional discussion has been added relating to the Edinburgh Low Emission Zone (LEZ) and other factors that may have influenced travel behaviour during the study period. To enhance clarity, some of the original figures and tables have been condensed or removed in the revised version. Specifically, we have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. We have removed Figures 8 and 16, which had small sample sizes. More information is provided on the demographics of the survey respondents in comparison to the general population of Edinburgh. See the authors' detailed response to the review by Rosemary McEachan See the authors' detailed response to the review by Sean Beevers Urban transportation has been linked to at least 14 pathways to health. Benefits, such as opportunities for physical activity, are relevant for active and sustainable travel, whereas negative impacts, including air pollution, stress, and road traffic injuries, relate to motorised transport (Glazener et al., 2021). According to the Scottish Health Survey (Birtwistle et al., 2022), over one third (35%) of adults did not meet the UK physical activity guidelines. As physical activity has broad physical and mental health benefits (Anderson & Durstine, 2019), active travel (i.e., ‘travel in which the sustained physical exertion of the traveller directly contributes to their motion’ [Cook et al., 2022]) may be an important way to help meet physical activity guidance for optimal health. Low Emission Zones (LEZs) aim to improve air quality by restricting the most polluting vehicles in certain areas (typically city centres with higher air pollutant concentrations). Fines are issued for vehicles that do not comply with emission standards (Broster & Terzano, 2024). LEZs have been associated with reductions in air pollutants, especially particulate matter of <2.5 µm (PM2.5) and nitrogen dioxide (NO2) (Broster & Terzano, 2024), as well as cardiovascular disease (Chamberlain et al., 2023) and paediatric respiratory admissions (Wise, 2024). Research has associated the implementation of LEZs with an acceleration of cleaner vehicles (Ellison et al., 2013), as well as a decrease in private vehicle use and increase in public transport (Tarriño-Ortiz et al., 2022). Active travel has been linked to the London Ultra-LEZ, which at present covers all London boroughs (TfL, 2023). Bike sharing rose by nearly 30%, notably for short and intermediate trips (Ding et al., 2023), and children attending schools within London’s Ultra-LEZ were three times more likely to switch to active travel after one year (Xiao et al., 2024). Nevertheless, LEZs may have real or perceived negative impacts, such as social exclusion (De Vrij & Vanoutrive, 2022) or displacement of traffic elsewhere (Moral-Carcedo, 2024). The City of Edinburgh, UK commenced LEZ enforcement in June 2024. Our study (TRAVel behaviour & Edinburgh Low Emission Zone [TRAVEL]) involved an online survey to extend the limited evidence base on how LEZs are associated with active travel. We formulated the following two research questions to compare travel inside and outside the Edinburgh LEZ, as well as before and after enforcement: A stakeholder group was established early in the TRAVEL study, which included representatives from City of Edinburgh Council, Public Health Scotland, Sustrans, NHS Lothian, Royal Town Planning Institute, Transport Scotland, and a local community member. This group provided input into the survey content and language, recruitment of potential survey respondents via social media advertising, and interpretation of results. This group will also assist with the dissemination of study findings. Setting. Edinburgh has a population of 500,000 (CEC, 2023a) with an annual mean temperature of 13 °C and 128 days of rainfall on average (Met Office, 2024). Edinburgh has an extensive bus service with 110 million journeys recorded in 2023 (Lothian Buses, 2024). Bus travel is free for residents of Scotland under the age of 22 years, 60 years or older, or with a disability. Edinburgh also has a tramline and train station in the city centre. LEZ intervention. The LEZ was officially implemented on 31st May 2022 with a two-year grace period: enforcement of non-compliance fees (starting at £60 and doubling thereafter) commenced on 1st June 2024 (CEC, 2024b; CEC, 2024c). The LEZ allows entry of petrol cars/vans registered from 2006 with Euro 4 emission standards (Euro 6 for diesel cars/vans registered from 2015) (CEC, 2023b). Although 95% of petrol cars in Edinburgh were estimated to have been compliant at the time of LEZ implementation, only 50% of diesel cars met the required standard (CEC, 2023c). Funds were made available to support low-income households with the disposal of vehicles that were not LEZ-compliant, as well as vouchers for the purchase of bikes or public transport tickets (CEC, 2024a). The LEZ is to ensure NO2 concentrations are below regulatory limits, to encourage more sustainable and active journeys, and to contribute to achieving net zero emissions by 2030. The LEZ covers <3% of the city with a total area of 3.1 km2 (CEC, n.d.), mainly including the city centre (Figure 1). Survey design. To answer the two main research questions, the survey collected data on demographics, travel habits, and reasons for travel choices. To explore modal change, questions addressed travel behaviour prior to the LEZ enforcement (pre-June 2024), as well as at the time of survey submission (October–November 2024). We included, as a measure of self-reported health, personal wellbeing questions (ONS, 2016). The main focus of the survey was the commute to work or study, with questions included for non-commute (i.e., other) travel. In summary, the questionnaire included the following content: Commute frequency, mode, duration (separately for inside/outside the LEZ) Any changes to the above (with reasons) since LEZ enforcement Non-commute travel inside the LEZ Changes in travel behaviour due to knowledge of the LEZ Agreement on potential impacts of the LEZ Age, sex, self-reported health and wellbeing We developed the questionnaire with a professional survey company (Civica). The survey was hosted on Civica’s external survey platform, Alchemer, for which Civica have a license. The survey was piloted for clarity and ease of completion with colleagues not on the project team and was designed to be completed within 15–20 minutes. The introductory webpage that potential respondents were directed to was used as the participant information sheet. Participants provided explicit written agreement to complete the survey before progressing to the questions. The study protocol was published on Research Registry on 30th July 2024 (UIN: researchregistry10542), and the Reading Independent Ethics Committee approved the study on 23rd August 2024 (reference: 230824). Survey recruitment. The target audience was adults (≥18 years old) working or studying in Edinburgh. We aimed to obtain responses from 350 individuals, using quotas to ensure representativeness in age and sex, as well as to limit respondents who did not commute (e.g., remote work/study only), but travelled to the LEZ for other reasons. The sample size was estimated using figures from the 2011 Scotland census as the most recent data available: a population size of 300,000 for the number of workers in Edinburgh, proportion of commute mode ranging from 5% (cycle) to 33% (car), margin of error of 5%, and a 95% confidence interval. Individuals were identified, screened, and recruited through an existing panel of potential survey respondents (managed by Dynata) living in the Edinburgh area. Individuals accessed the survey through a weblink, which opened to a webpage describing the study’s purpose, content, and use of data. To maximise the number of respondents, the survey was also made available on the IOM website and was advertised by organisations represented on the stakeholder group; thus, there were two versions of the survey for ‘panel’ and ‘community’ respondents (full survey version available at https://osf.io/at8sv/). No additional payments or incentives were provided for completion of the survey; however, panel respondents do receive point incentives for each survey completed. Statistical analysis. We were interested in comparing travel behaviour of those commuting inside the LEZ to that of those whose commute did not traverse the LEZ. For the purposes of the survey, inside the LEZ was defined as a journey that passed through or included any part of the LEZ, whereas journeys outside the LEZ did not enter the LEZ at any point. The main analysis involved summary statistics of main survey questions and comparing travel behaviour responses by inside/outside LEZ commuters. Statistical analysis was undertaken to compare differences in commuting behaviour and perspectives before/after LEZ enforcement and whether travel involved the LEZ. We used several different methods depending on whether the data was categorical (chi-squared), Normal (t-test)/non-Normal (Kruskal-Wallis), paired (Wilcoxon signed rank test), or proportions (equality of proportions). The modes of transport were grouped into public transport (train, tram, and bus), active travel (bike, scooter, walk, and run), and vehicle (all other modes). Area-level deprivation (i.e., by datazone) was assigned using deciles of the Scottish Index of Multiple Deprivation (SIMD) matched to postcode. Respondents had the opportunity to include as free text any further comments on the LEZ. These remarks were broadly classified into positive (i.e., in support of the LEZ), negative (i.e., opposed to the LEZ), or neutral (i.e., neither in support nor opposed). Analysis was stratified for the panel and community respondents, given the different recruitment methods. Only fully completed surveys were included in the data analysis, which was performed using R (R Core Team, Vienna, Austria). Carbon emissions. As an additional analysis, given the LEZ will contribute to Edinburgh’s 2030 Climate Strategy (CEC, 2021), we analysed the total commuting carbon emissions before and after enforcement for single modes of those commuting inside the LEZ. Emission estimates were based on reported mode, duration, and weekly frequency. As we did not have data on distance travelled, we estimated speed by mode via published sources, including the Physical Activity compendium (Hermann et al., 2024). The following speeds were used for the single modes reported in the panel survey results: Train: It was assumed that people were commuting or travelling into Edinburgh from a distance of 30 km or less; for this line length the average train speed is about 60 km/h (17 m/s) (Jiang et al., 2024). Car: Traffic was monitored before and after 20 mph zones were introduced in Edinburgh. The city centre speed after implementation was measured as 22 mph (10 m/s) (Nightingale et al., 2021) Bus: Assumed to be the same speed as a car. Although they stop more frequently (i.e., slower speeds), they also have access to bus lanes (i.e., faster speeds during periods of high traffic) Van: Assumed to be the same speed as a car Cycling: 12–13.9 mph, leisure, moderate effort, 13 mph used as mid-point of moderate effort: 13 mph=5.8 m/s Walking: 2.8 to 3.4 mph, level, moderate pace, firm surface Mid-point=3.1 mph (1.4 m/s) The following list presents carbon footprints per km for each transport mode. These estimates are based on Our World in Data (2023), unless otherwise stated. Car (diesel): 171 g Car (petrol): 170 g Van: 170 g Car (non-plug in hybrid): 119 g (midpoint between petrol and hybrid car) Bus: 97 g Car (hybrid): 68 g Walking: 55 g Car (electric): 47 g Cycling: 35 g (midpoint from Leurent [2022]) Train: 35 g Traffic displacement. The minimum distance from the full home postcode to the nearest segment of the LEZ boundary was calculated for each respondent using the open-source software, QGIS (v3.30.0) (https://qgis.org). To examine any potential traffic displacement, taking account of the potential discrepancy between reporting of postcodes and living inside/outside the LEZ boundary, we compared two sets of respondents who reported “more traffic” or “less traffic” as a reason for any changes to frequency, duration, or mode in commute or other travel. The data for inside and outside commuters, as well as people who travel to the LEZ for other reasons, was used for this analysis. One set of respondents included those who reported living inside or outside the LEZ, and the other set used postcodes to define living inside, ≤1 km outside the boundary, or >1 km outside the boundary. The latter set excluded any respondents who reported living inside the LEZ, but did not have an outcode within the LEZ (i.e., EH1, EH2, EH3, or EH8). Both surveys were available from 4th October, with the panel survey remaining open until 14th October and the community version closing on 15th November 2024. A total of 351 respondents completed the panel survey and a further 260 submitted the community version (i.e., total n=611). Thirty-four respondents were disqualified from the panel survey and eight from the community survey for answering “No” to the question, “Do you agree to provide feedback about Edinburgh’s Low Emission Zone?”, or not commuting or travelling to the LEZ for other reasons. There were similar proportions of males (167; 48%) and females (179; 51%) in the panel version, with proportionally slightly more male respondents (145; 56%) in the community survey. There was a greater number of respondents aged 24–44 years in the panel version, with fewer respondents in the youngest and oldest age brackets in the community survey (see Table 1). In both surveys, and more prominently in the community results, the mode SIMD was decile 10 (i.e., least deprived) (see Table 1). Self-reported happiness and wellbeing were generally high in both the panel and community surveys, with 75% or more respondents scoring 6 or above on an 11-point scale with 10 being the highest. The response to the question, ‘How anxious did you feel yesterday?’, had a more uniform distribution across the 11-point scale for both the panel and community results. More respondents commuted inside the LEZ in the panel (n=178, 51%) and community (n=174, 67%) surveys than outside the LEZ boundary (panel n=89, 25%; community n=52, 20%). Table 2 presents current commuting frequency, mode, and duration separately by travel inside and outside the LEZ for both the panel and community surveys. Respondents who reported travelling to the LEZ for other reasons (panel n=83, 24%; community n=34, 13%) are presented separately in Table 3. The frequency of travel was different inside and outside the LEZ (panel only), and using a single transport mode was more common inside the boundary. Commute durations were higher inside the LEZ than outside, though with high variability (Table 2). | Commuting characteristics | Panel survey | Community survey | |||| |---|---|---|---|---|---|---| | Inside | Outside | p-value | Inside | Outside | p-value | | | Frequency (weekly) 5 | 10 [5.6] 15 [8.4] 34 [19.1] 34 [19.1] 18 [10.1] 49 [27.5] 18 [10.1] | 18 [20.2] 3 [3.4] 15 [16.9] 12 [13.5] 11 [12.4] 28 [31.5] 2 [2.2] | 0.002 | 10 [5.7] 21 [12.1] 21 [12.1] 49 [28.2] 20 [11.5] 40 [23.0] 13 [7.5] | 3 [5.8] 5 [9.6] 5 [9.6] 9 [17.3] 4 [7.7] 22 [42.3] 4 [7.7] | 0.220 | | Transport mode Single Multiple* | 86 [48.3] 92 [51.7] | 67 [75.3] 22 [24.7] | <0.001 | 96 [55.2] 78 [44.8] | 37 [71.2] 15 [28.8] | 0.020 | | Duration in minutes (median [IQR**]) Single Multiple* | 38 [31] 66 [63] | 22 [28] 44 [44] | 0.017 0.691 | 38 [23] 91 [59] | 22 [16] 67 [60] | 0.529 0.340 | | Number of respondents | 178 (51) | 89 (25) | N/A | 174 (67) | 52 (20) | N/A | | Other travel characteristics | Survey | | |---|---|---| | Panel | Community | | | Frequency (weekly) 5 | 42 [50.6] 16 [19.3] 9 [10.8] 9 [10.8] 5 [6.0] 1 [1.2] 1 [1.2] | 9 [26.5] 4 [11.8] 4 [11.8] 7 [20.6] 4 [11.8] 1 [2.9] 5 [14.7] | | Transport Mode Single Multiple | 39 [47.0] 44 [53.0] | 7 [20.6] 27 [79.4] | | Duration (median [IQR*]) Single Multiple | 22 [16] 63 [53] | 22 [8] 60 [46] | | Total | 83 | 34 | The most common five modes of transport reported in the panel survey were bus, car (alone), walk, train, and tram. The corresponding list in the community survey was slightly different, including walk, bus, car (alone), bike, and electric bike (see Figure 2 for the full list of selected transport modes). For the panel survey, there was a clear differentiation (p<0.001) with more people using the car alone for their commute outside the LEZ. More people tended to use the bus inside the LEZ (p=0.010). There were borderline significant differences in the proportions inside and outside the LEZ using bus & walk (p=0.110) and walking (p=0.054), but these comparisons were based on few respondents. There were similar findings in the community survey to that of the panel relating to use of the car, bus, and walking, with no difference in the proportion of people who cycle inside and outside the LEZ (p=0.439) (see Figure 3). The reasons for using a given transport mode are depicted in Figure 4. For brevity, and since the three most common overall modes in the panel and community surveys were the same (Figure 2), we present the individual reasons for commuting by car (alone), bus, and walking. As suggested by Figure 4, there are generally more differences between modes than either commuting inside or outside the LEZ or between the panel and community surveys. While convenience is clearly an important consideration for a given mode, ‘better for mental health’ and ‘healthier’ were much more common reasons for walking than car or bus. Most respondents did not change whether they commuted inside or outside the LEZ following enforcement in June 2024, though more travel changes were observed for those commuting inside the LEZ (see Table 4). Of the 159 inside LEZ commuters in the panel survey, 70 (44%) reported a change in the frequency, duration, or mode of transport versus 8 out of 77 (10%) for the commuters outside of the LEZ. A similar trend was noted in the community survey, though to a lesser extent: 41 out of 171 (24%) of inside LEZ commuters reported such changes compared to 4 out of 47 (9%) of the outside commuters. The most common reason cited for a change in commute was “circumstance change”. For the frequency of commuting, there was no general trend following LEZ enforcement in either the panel or community surveys (Figure 5). However, the three most common reasons given in the panel survey (i.e., ‘quicker’, ‘more convenient’, ‘cheaper’) implied increasing frequency, whereas those in the community survey (i.e., ‘longer’, ‘less convenient’, ‘expensive’) suggested less frequent commuting (Figure 6). A similar trend of disparate results between the panel and community surveys was also evident for changes in commute duration. The most reported reasons in the panel survey were ‘less traffic’, ‘public transport more reliable’, and ‘cycle routes improved’, indicating faster commute durations, in contrast to ‘more traffic’, ‘public transport less reliable’, and ‘different route’ (omitting ‘other’), as noted in the community survey (Figure 6). The shift in commute mode showed a general decline in the reporting of private vehicle use following the LEZ enforcement (Figure 6). When categorising reported changes in commute modes for those commuting inside the LEZ before and after enforcement based on any active travel (i.e., including multiple modes), there was an increase in prevalence following enforcement in the panel (n=53/178, 30% vs n=62/178, 35%) (Wilcoxon signed rank test p=0.014) and to a lesser extent in the community survey (n=103/174, 59% vs n=108/174, 62%) (Figure 7). The survey question regarding multiple commute modes contained up to 10 different reported modes of transport, suggesting respondents may have entered all possible modes of transport rather than only those used for a typical commute. Therefore, we limited the analysis of active travel minutes to respondents reporting a single travel mode (i.e., participants reporting multiple travel modes were excluded) (Table 5). For insider commuters reporting a single mode, the median commute time was 22 minutes for both the panel and community survey (panel before [n=6] and after [n=5], community before [n=34] and after [n=34] LEZ enforcement). The weekly carbon emissions combined for respondents using a single mode prior to LEZ enforcement was 405 kg, which is only slightly higher than the combined emissions following enforcement (404 kg) (p=0.798) (see Figure 8). The survey asked participants explicitly about any changes prompted by their knowledge of the LEZ. Although the most frequent response was ‘none of the above’ for inside and outside LEZ commuters, more than half (n=107, 60%) and over one third (n=63, 36%) of inside commuters changed one or more travel behaviours in the panel and community surveys, respectively. Such behaviours included using public transport more and walking/cycling more. About 40% of outside LEZ commuters in each survey reported such changes (see Figure 9). For shorter journeys (defined as up to 5 miles), a greater proportion of those commuting inside the LEZ made changes to these journey types compared to those commuting outside the LEZ in the panel (n=98/178, 55% vs n=19/89, 21%), but not community (n=36/174, 21% vs n=11/52, 21%) survey (see Figure 10). The survey included questions on agreement related to seven specific impacts of the LEZ (e.g., reducing air and noise pollution). Responses to each of the individual impacts were broadly similar in the panel survey, with less than 25% disagreement and at least a 2:1 ratio of agreement to disagreement. The community survey suggested lower agreement overall and more variation across the different potential impacts; most agreement was indicated for ‘reduce air pollution’ and the most disagreement was for ‘encourage active travel’ (Figure 11). Respondents who did not commute for work or study reported other travel to the LEZ area (panel n=83, 24%; community n=34, 13%). The purpose of these journeys was predominantly for leisure or appointments, and the frequency was less often than that reported for commuters. Less than a third of these respondents (panel n=20, 24%; community n=10, 29%) reported changes (i.e., frequency, duration, mode) to their travel since enforcement. As observed in the results of those commuting into the LEZ, there was a general shift away from private vehicle use (though based on a smaller sample) (other travel results are presented in Table 3). There were 85 of the 351 (24%) respondents that reported living within the LEZ boundary. The main outcodes (i.e., first 3–4 digits of full postcode) within the LEZ are EH1, EH2, EH3 and EH8; 30 of the 85 reported living in one of these outcodes. Potential reasons for this discrepancy could be due to confusion about the specific location of the LEZ, having multiple home addresses, or reporting postcodes inaccurately. Overall, 55 people entered “More traffic” or “Less traffic” as a reason for a change to their commute/travel. Of these 55, 20 were excluded in the postcode analysis, as noted above. There did not appear to be evidence of more traffic outside the LEZ in either the postcode or self-reported data analysis (see Figure 12). Free text comments were more prevalent in the community survey (n=147/260, 57%) than submitted in the panel version (n=128/351, 36%). The panel survey comments reflected more positive LEZ sentiments than those of the community respondents (n=56/128, 44% vs n=35/147, 24%). This study represents early results of travel behaviour and impacts of enforcement of the Edinburgh LEZ, with a focus on commuting for work or study. The most frequently reported commute modes overall were bus, car, and walking, with private car use more commonly reported for journeys that excluded the LEZ. Travel via the LEZ area was largely unchanged following enforcement, yet there were more changes in the frequency, duration, or mode in commutes that included the LEZ compared to those that did not. Initial results indicate more changes to shorter journeys for those commuting inside the LEZ, as well as a slight shift to more active travel. Nevertheless, some findings were mixed between respondents recruited by the two different methods. It is perhaps not surprising that private car use was more common outside than inside the LEZ boundary. In general, city centres, where LEZs tend to exist, entail greater densities of services, more public transport options, and potential impediments to car use (e.g., higher cost/less availability of parking), thus facilitating other modes of transport (Dempsey et al., 2012). Nevertheless, other LEZs, such as Lisbon, have noted reductions in traffic of 3–4% both inside and outside the LEZ boundary, with a greater share of cars with higher emission standards (Ferreira et al., 2015). A 50% decrease in Euro 3 (and lower) vehicles was noted following the introduction of the Rotterdam LEZ, though these particular vehicles represented only 2% overall of those entering the LEZ area. This underscores that LEZs, depending on the specific parameters, may prevent only the most polluting vehicles and not necessarily traffic in general (Attia et al., 2023). Data available from Edinburgh Council suggests a decline in the number of non-compliant vehicles since enforcement began (CEC, 2024b). An analysis of the Madrid LEZ found less traffic flow and greater public transport use into the LEZ, with some evidence of displacement (i.e., greater traffic levels) outside the boundary (Tassinari, 2024). Our study specifically examined commuting to study/work, which may be different than travelling for other reasons, though we also collected this data from non-commuting respondents. Commuting behaviour may be distinct, as a study in China found individuals to be less likely to choose bus/walking during peak hours or when going to work (Luan et al., 2020). Such an effect, if relevant for the current study, would have led to an overestimate of overall car use to access the LEZ. LEZ enforcement did not appear to influence whether a commuting journey included the LEZ area. Significant commute changes are more likely to occur after moving home or changing employer (Clark et al., 2016). Nevertheless, there were more changes to the nature of the commute for those traversing the LEZ compared to those who did not. Following implementation of the Madrid LEZ, there was an observed 29 percentage point decline in private vehicle use, with 9 and 8 percentage point increases in public transport and active travel, respectively (Tarriño-Ortiz et al., 2022). Our results also indicated an increase in LEZ commutes with public transport and active travel, either as a component of or for the entire journey. These results coincide with a greater proportion reporting, as a result of the LEZ, walking, cycling or using public transport for shorter journeys inside compared to outside the LEZ, at least in the panel survey. Lower observed increases in active travel in the community survey could be due to a greater number of active travel users at baseline, as observed elsewhere (Le Gouais et al., 2021). Other studies have shown increases in public transport both inside and outside of the boundary, such as for the Rotterdam LEZ (Attia et al., 2023). However, such changes are not universal and may be context-specific: the Bradford Clean Air Zone, which charges larger vehicles (e.g., buses), but not private vehicles, found an overall increase in private transport to get to work (Mebrahtu et al., 2024). While the Edinburgh LEZ penalises cars below certain emission standards, the presence of an LEZ could raise awareness of environmental issues, such as air pollution and traffic, possibly leading to pro-environmental behaviour, including reduced car use (PHS, 2023). Interestingly, in the case of the panel survey, there were similar levels of agreement across potential LEZ impacts, even for those which are less studied, such as noise reduction (Andriolli & Silva, 2024). The free-text comments were more pro-LEZ in the panel compared to the community survey responses. With no comparable incentives, the community respondents’ stronger opinions about the LEZ or LEZ-related matters may have motivated their participation. Mebrahtu et al. (2024) also used two recruitment strategies (i.e., existing cohort and public samples) and found the public respondents to be more concerned about air quality issues. There are numerous considerations for travel choices, including personal, socioeconomic, infrastructure and others (Dingil et al., 2021). A survey following LEZ implementation in Madrid found the most common reasons for transport choice were comfort, travel time, cost (Tarriño-Ortiz et al., 2022). These were also important motivations for travel mode in our survey, as well as the healthier option for non-motorised travel. Our study has several strengths. The survey represents short-term results of the travel behaviour impacts and perspectives from commuters on the enforcement of the Edinburgh LEZ. We collected detailed information involving travel inside and outside the LEZ, and before and following enforcement using two recruitment methods. To help with understanding the impacts, we included questions on specific actions attributed to knowledge/awareness of the LEZ. Several limitations should be noted with the interpretation of our results. Our survey used a cross-sectional approach and relied on the recall of individuals of travel behaviour prior to LEZ enforcement. While self-reported travel behaviour has been shown to be reliable at the group level (Kelly et al., 2014), recall of pre-enforcement travel may have been less accurate, particularly if the start of LEZ enforcement was not a particularly salient event (Müggenburg, 2021). The use of objective data to assess traffic volumes or public transport use, for example, should be undertaken to compare with analyses based on subjective inputs (Tassinari, 2024). Travel behaviour may have differed by season between the current (i.e., October/November) and pre-enforcement (i.e., pre-June) timelines. Some respondents may have been less likely to engage in active travel during potentially cooler and darker conditions as reported in the ‘current’ time-period, the impact of which may have downplayed any positive associations following LEZ enforcement (Brainard et al., 2019). Impacts may have been underestimated, given the LEZ was implemented two years earlier (without issuing non-compliance fees); individuals may have undertaken specific changes prior to enforcement, which would not have been captured through the analysis of travel before and after enforcement. Nevertheless, we did ask about the replacement of non-compliant vehicles, which applied to a minority of respondents: four of eight individuals commuting inside the LEZ reported upgrading their non-compliant vehicle. Survey questions related to behaviour changes due to knowledge of the LEZ and agreement on potential LEZ impacts did not specify ‘enforcement’, so it was not possible to distinguish effects from implementations versus enforcement in those responses. There were two notable issues with the collection of multi-modal data. First, it was apparent that the reporting of multiple modes may have represented separate commute journeys, which, if combined, would have overestimated commute duration. Second, the survey did not distinguish mode-specific duration of pre-enforcement travel. Thus, it is important for travel surveys to use explicit language for multi-modal travel to be able to answer the relevant research questions. There were inconsistencies between the locations of postcodes and whether a respondent reported living inside the LEZ. This weakened our ability to examine potential traffic displacement experienced by those living in close proximity to the LEZ boundary. Surveys were completed 4–5 months following the start of enforcement, so our results represent short-term findings, which should be compared with results over a longer follow-up period. The focus of our survey was on LEZ enforcement, though other concurrent policy/infrastructure changes may have influenced travel behaviour. For example, several respondents selected ‘cycle routes improved’ as the reason for changes in duration. The City of Edinburgh also increased parking fees (CEC, 2024d) and introduced new cycle lanes in the city centre (Walk Wheel Cycle Trust, 2024) only months before LEZ enforcement, potentially further discouraging private vehicle use. Subsequent research should examine LEZ enforcement impacts in the broader context of other mobility-related policies in Edinburgh and other urban settings. In both the panel and community surveys, the proportions of respondents were mainly distributed across ages 25-64, though with lower proportions of 18-24-year olds compared to Edinburgh, particularly in the community cohort (NRS, 2025). This demographic may have been less likely to receive/respond to online promotional content from the organisations involved in the study stakeholder group. More respondents were from the least deprived quintile according to the national SIMD rankings (panel: 31%; community: 40%), which is representative, but lower in fact, than the whole of Edinburgh (45%) (CEC, 2020). Therefore, our findings may be less reflective of younger Edinburgh residents living in more deprived areas. We conducted a cross-sectional survey to understand the early impacts of the Edinburgh LEZ enforcement on travel behaviour and perspectives. We found some evidence that active travel and the use of public transport increased inside the LEZ boundary. Future research should confirm our findings with objective data and assess impacts over a longer time-period. Ethical approval for the study was granted by the Reading Independent Ethics Committee (RIEC) on 23 August 2024 (reference: 230824). Participants provided explicit written agreement to complete the survey before progressing to the questions. OSF: TRAVel Behaviour & Edinburgh Low Emission Zone. DOI: https://doi.org/10.17605/OSF.IO/AT8SV (Mueller, 2025) This project contains the following underlying data: Data are available under the terms of the CC-By Attribution-NonCommercial-NoDerivatives 4.0 International William Mueller: Conceptualisation, Methodology, Writing – Original draft, Funding acquisition. Fiona Carson: Formal analysis, Methodology, Writing – reviewing and editing. Helena Copsey: Project administration, Writing – reviewing and editing. Miranda Loh: Methodology, Writing – reviewing and editing. The TRAVEL study questionnaire and anonymised data are published on OSF (http://doi.org/10.17605/OSF.IO/AT8SV). IOM is committed to handling all personal information in line with the UK Data Protection Act (2018) and the General Data Protection Regulation (EU GDPR) 2016/679. Under the Data Protection legislation, IOM is the Data Controller, and you can find out more about how we handle personal data, including how to exercise your individual rights and the contact details for our Data Protection Officer here. We acknowledge the valuable input from Civica (Tricia Smith, Elizabeth Hickey) to develop the online survey. We are grateful to the individuals on the steering committee (Dr Paul Kelly, Prof Rachel Aldred, Dr Tom Clemens, Prof Peter Craig, Dr Audrey de Nazelle, Prof Georgina Santos, Dr Eric Deeson) and stakeholder group (Dr Margaret Douglas, Jenny Munro, Dr Andy Cope, John Brennan, Vincent McInally, George King, Shauna Clarke, Ruth White, Judith Cowie, and Scott Walkingshaw). Faculty Opinions recommendedReferences - Anderson E, Durstine JL: Physical activity, exercise, and chronic diseases: a brief review. Sports Med Health Sci. 2019; 1(1): 3–10. PubMed Abstract | Publisher Full Text | Free Full Text - Andriolli AC, Silva LT: Are Low Emission Zones truly embraced by the public? Environments. 2024; 11(6): 106. Publisher Full Text - Attia M, Alade T, Attia S: The influence of passenger car banning policies on modal shifts: Rotterdam’s case study. Sustainability. 2023; 15(9): 7443. Publisher Full Text - Birtwistle S, Deakin E, Wildman J, et al.: The scottish health survey 2022–volume 1: main report. Scottish Government, 2022. Reference Source - Brainard J, Cooke R, Lane K, et al.: Age, sex and other correlates with active travel walking and cycling in England: analysis of responses to the active lives survey 2016/17. Prev Med. 2019; 123: 225–231. PubMed Abstract | Publisher Full Text - Broster S, Terzano K: A systematic review of the pollution and health impacts of Low Emission Zones. Case Stud Transp Policy. 2024; 19: 101340. Publisher Full Text - Chamberlain RC, Fecht D, Davies B, et al.: Health effects of low emission and congestion charging zones: a systematic review. Lancet Public Health. 2023; 8(7): e559–e574. PubMed Abstract | Publisher Full Text - City of Edinburgh Council (CEC): Briefing Note – Scottish Index of Multiple Deprivation, 2020. 2020; Last accessed 24 September 2025. Reference Source - CEC: 2030 Climate Strategy – delivering a net zero, climate ready city. 2021; Last accessed 17 November 2025. Reference Source - CEC: Edinburgh by numbers: 2023. 2023a; Last accessed 20 December 2024. Reference Source - CEC: Low Emission Zone (LEZ). 2023b; Last accessed 20 December 2024. Reference Source - CEC: Low Emission Zone compliance rates rise as countdown to enforcement continues. 2023c; Last accessed 22 January 2025. Reference Source - CEC: Low Emission Zone - support and funding. 2024a; Last accessed 10 January 2025. Reference Source - CEC: Low Emission Zone (LEZ) penalty charges. 2024b; Last accessed 10 January 2025. Reference Source - CEC: Low Emission Zone enforcement begins in Edinburgh. 2024c; Last accessed 20 January 2025. Reference Source - CEC: New parking rules. 2024d; Last accessed 14 November 2025. Reference Source - CEC: Background to the Low Emission Zone. n.d.; Last accessed 20 January 2025. Reference Source - Clark B, Chatterjee K, Melia S: Changes to commute mode: the role of life events, spatial context and environmental attitude. Transp Res Part A Policy Pract. 2016; 89: 89–105. Publisher Full Text - Cook S, Stevenson L, Aldred R, et al.: More than walking and cycling: what is ‘active travel’? Transp Policy. 2022; 126: 151–161. Publisher Full Text - De Vrij E, Vanoutrive T: ‘No-one visits me anymore’: Low Emission Zones and social exclusion via sustainable transport policy. J Environ Policy Plan. 2022; 24(6): 640–652. Publisher Full Text - Dempsey N, Brown C, Bramley G: The key to sustainable urban development in UK cities? The influence of density on social sustainability. Prog Plann. 2012; 77(3): 89–141. Publisher Full Text - Ding H, Sze NN, Guo Y, et al.: Effect of the Ultra-Low Emission Zone on the usage of public bike sharing in London. Transportation Letters. 2023; 15(7): 698–706. Publisher Full Text - Dingil AE, Rupi F, Esztergár-Kiss D: An integrative review of socio-technical factors influencing travel decision-making and urban transport performance. Sustainability. 2021; 13(18): 10158. Publisher Full Text - Ellison RB, Greaves SP, Hensher DA: Five years of London’s Low Emission Zone: effects on vehicle fleet composition and air quality. Transp Res D Transp Environ. 2013; 23: 25–33. Publisher Full Text - Ferreira F, Gomes P, Tente H, et al.: Air quality improvements following implementation of Lisbon's Low Emission Zone. Atmos Environ. 2015; 122: 373–381. Publisher Full Text - Glazener A, Sanchez K, Ramani T, et al.: Fourteen pathways between urban transportation and health: a conceptual model and literature review. J Transp Health. 2021; 21: 101070. Publisher Full Text - Herrmann SD, Willis EA, Ainsworth BE, et al.: 2024 adult compendium of physical activities: a third update of the energy costs of human activities. J Sport Health Sci. 2024; 13(1): 6–12. PubMed Abstract | Publisher Full Text | Free Full Text - Jiang K, Tian Z, Wen T, et al.: Cost modelling-based route applicability analysis of United Kingdom passenger railway decarbonization options. International Journal of Electrical Power & Energy Systems. 2024; 160: 110094. Publisher Full Text - Kelly P, Doherty A, Mizdrak A, et al.: High group level validity but high random error of a self-report travel diary, as assessed by wearable cameras. J Transp Health. 2014; 1(3): 190–201. Publisher Full Text - Le Gouais A, Panter JR, Cope A, et al.: A natural experimental study of new walking and cycling infrastructure across the United Kingdom: the connect2 programme. J Transp Health. 2021; 20: 100968. Publisher Full Text - Leurent F: From food to foot: the energy and carbon flows of the human body at walking and cycling. J Energy Power Technol. 2022; 4(3): 025. Publisher Full Text - Lothian Buses: 110 million customer journeys recorded onboard Lothian. 2024; Last accessed 7 January 2025. Reference Source - Luan X, Cheng L, Song Y, et al.: Better understanding the choice of travel mode by urban residents: new insights from the catchment areas of rail transit stations. Sustain Cities Soc. 2020; 53: 101968. Publisher Full Text - Mebrahtu T, McEachan RRC, Knamiller C, et al.: Does implementation of a Low Emission Zone change perceptions of air quality, acceptability and travel behaviour? A longitudinal and repeated cross-sectional survey study in Bradford, UK [version 2; peer review: 2 approved]. NIHR Open Res. 2024; 4(71): 71. Publisher Full Text - Met Office: Location-specific long-term averages. 2024; Last accessed 20 December 2024. Reference Source - Moral-Carcedo J: Dissuasive effect of Low Emission Zones on traffic: the case of Madrid Central. Transportation. 2024; 51(1): 25–49. Publisher Full Text - Müggenburg H: Beyond the limits of memory? The reliability of retrospective data in travel research. Transp Res Part A Policy Pract. 2021; 145: 302–318. Publisher Full Text - Mueller W: TRAVel Behaviour & Edinburgh Low Emission Zone. 2025. http://www.doi.org/10.17605/OSF.IO/AT8SV - National Records of Scotland (NRS): Council area profile: Edinburgh City. 2025; Last accessed 24 September 2025. Reference Source - Nightingale GF, Williams AJ, Hunter RF, et al.: Evaluating the citywide Edinburgh 20mph speed limit intervention effects on traffic speed and volume: a pre-post observational evaluation. PLoS One. 2021; 16(12): e0261383. PubMed Abstract | Publisher Full Text | Free Full Text - ONS: Personal well-being in the UK QMI newport: office for national statistics 2016. 2016. Reference Source - Our World in Data: Which form of transport has the smallest carbon footprint? 2023; Last accessed on 15th January 2025. Reference Source - Public Health Scotland (PHS): Evaluability assessment of Low Emission Zones: Glasgow Low Emission Zone. 2023; Last accessed 8 January 2025. Reference Source - Tarriño-Ortiz J, Gómez J, Soria-Lara JA, et al.: Analyzing the impact of Low Emission Zones on modal shift. Sustain Cities Soc. 2022; 77: 103562. Publisher Full Text - Tassinari F: Low Emission Zones and traffic congestion: evidence from Madrid central. Transp Res Part A Policy Pract. 2024; 185: 104099. Publisher Full Text - Transport for London (TfL): ULEZ Expansion 2023. 2023; Last accessed 20 January 2025. Reference Source - Walk Wheel Cycle Trust: New multi-million pound cycling route in Edinburgh city centre officially open. 2024; Last accessed 14 November 2025. Reference Source - Wise J: Paediatric respiratory admissions decreased in Birmingham's clean air zone, data show. BMJ. 2024; 387: q2369. PubMed Abstract | Publisher Full Text - Xiao C, Scales J, Chavda J, et al.: Children’s Health in London and Luton (CHILL) cohort: a 12-month natural experimental study of the effects of the Ultra Low Emission Zone on children’s travel to school. Int J Behav Nutr Phys Act. 2024; 21(1): 89. PubMed Abstract | Publisher Full Text | Free Full Text Author details Author details 1 Institute of Occupational Medicine (IOM), Research Ave N, EH14 4AP, Edinburgh, UK William Mueller Roles: Conceptualization, Funding Acquisition, Methodology, Writing – Original Draft Preparation Roles: Conceptualization, Funding Acquisition, Methodology, Writing – Original Draft Preparation Fiona S. Carson Roles: Formal Analysis, Methodology, Writing – Review & Editing Roles: Formal Analysis, Methodology, Writing – Review & Editing Helena Copsey Roles: Project Administration, Writing – Review & Editing Roles: Project Administration, Writing – Review & Editing Miranda Loh Roles: Methodology, Writing – Review & Editing Roles: Methodology, Writing – Review & Editing Competing interests No competing interests were disclosed. Grant information This project is funded by the National Institute for Health and Care Research (NIHR) under its Public Health Research (PHR) Programme (Grant Reference Number NIHR167483). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Article Versions (2) Copyright © 2026 Mueller W et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. metrics VIEWS $counts.viewCount downloads Citations CITE how to cite this article Mueller W, Carson FS, Copsey H and Loh M. Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.13891.2) NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article. track receive updates on this article Track an article to receive email alerts on any updates to this article. Current Reviewer Status: ? Key to Reviewer Statuses VIEW HIDE ApprovedThe paper is scientifically sound in its current form and only minor, if any, improvements are suggested Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit. Not approvedFundamental flaws in the paper seriously undermine the findings and conclusions Version 2 VERSION 2 PUBLISHED 19 Jan 2026 Revised Views 0 How to cite this report: McEachan R. Reviewer Report For: Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.15454.r39203) The direct URL for this report is: https://openresearch.nihr.ac.uk/articles/5-33/v2#referee-response-39203 https://openresearch.nihr.ac.uk/articles/5-33/v2#referee-response-39203 NOTE: it is important to ensure the information in square brackets after the title is included in this citation. Reviewer Report 03 Feb 2026 Approved VIEWS 0 Thank you for considering the ... Continue reading I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. Close Thank you for considering the reviewers comments and revising accordingly. Competing Interests: No competing interests were disclosed. Reviewer Expertise: Complex intervention development and evaluation; evaluation of clean air zones; environmental determinants of health; cohort studies. CITE HOW TO CITE THIS REPORT McEachan R. Reviewer Report For: Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.15454.r39203) The direct URL for this report is: https://openresearch.nihr.ac.uk/articles/5-33/v2#referee-response-39203 https://openresearch.nihr.ac.uk/articles/5-33/v2#referee-response-39203 NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article. Version 1 VERSION 1 PUBLISHED 14 Apr 2025 Views 0 How to cite this report: Beevers S. Reviewer Report For: Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.15098.r36351) The direct URL for this report is: https://openresearch.nihr.ac.uk/articles/5-33/v1#referee-response-36351 https://openresearch.nihr.ac.uk/articles/5-33/v1#referee-response-36351 NOTE: it is important to ensure the information in square brackets after the title is included in this citation. Reviewer Report 25 Sep 2025 Sean Beevers, Imperial College London, London, UK Approved with Reservations VIEWS 0 Travel behaviour study Edinburgh LEZ This is a cross sectional survey looking at commuting behaviour inside and outside the Edinburgh LEZ. Key findings related to the mode usage, e.g. car, public transport inside and outside the LEZ zone with ... Continue reading I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. Close This is a cross sectional survey looking at commuting behaviour inside and outside the Edinburgh LEZ. Key findings related to the mode usage, e.g. car, public transport inside and outside the LEZ zone with ... Continue reading Travel behaviour study Edinburgh LEZ This is a cross sectional survey looking at commuting behaviour inside and outside the Edinburgh LEZ. Key findings related to the mode usage, e.g. car, public transport inside and outside the LEZ zone with a small shift to active travel and public transport in the LEZ. I think this is a useful paper, looking beyond the air pollution impacts at travel behaviour. I’ve made some suggestions for the authors to consider which I hope are useful.

There needs to be a sentence on why the panel and community surveys. Also when it says “There was a clear differentiation in transport mode usage, with more people using the car alone for their commute outside the LEZ and more people using public transport inside the LEZ” make it clear whether this is prior to the LEZ or because of the LEZ. Main text: Although some of these points are addressed as limitations in the discussion I think they are important in interpreting the data, so further comment on these would improve the paper. A description of travel in the LEZ zone c.f. outside would be useful – prior to implementation, during the grace period and once implemented. Were there changes to other travel modes e.g. bus frequency, parking availability, no of cycle routes etc, which may have influenced the choices and change in modes reported. You also mention vehicle compliance, high for petrol cars, half for diesel, how did this change over time through the grace period inside the LEZ and around full implementation in 2024 and how did this compare with Edinburgh in general. Could the authors comment on how the survey accounts for the fact that the effects of the LEZ start during the grace period (start date in 2022). How would it have influenced the results. Also, the survey was 5 months after the 2024 start date which requires responders to think back to before LEZ. Was this in the grace period or maybe before that? Can you comment on the reliability of this data. The manuscript would benefit from more detail on the two survey’s - not only how representative they were of the wider population but also what were the reasons for having both community and panel results. Was it to compared strongly held opinions (community involvement) with more general opinions (panel)? Also, a statement on the degree to which the panel and community samples are comparable and support your results would be useful. For example: Fig 2 show differences in age….Fig 3 the panel and community are quite different, especially at the low SIMD deciles. Both have dominant decile 10. This seems unusual? It wasn’t clear to me why it was important to ask about “happiness yesterday” etc? I think this needs an explanation. How do you account for seasonal effects in your questions/data analysis. For example, if you survey in Oct/Nov for things like cycling now and compare this with what you did before LEZ (pre June 2024). It was confusing to use CO2 emissions as a metric and not include Nox emissions to assess the impact of the travel behaviour of the scheme? Was CO2 reduction a stated aim of the LEZ? In the commute modes analysis, I was also a bit surprised that bike/e-bike wasn’t chosen as it was relatively important and the differences between panel and community was large, which tells you something…your background talked a lot about active travel so it would seem to be a useful addition. Figure 8 – tiny numbers – are these results sound? Figure 12 – was CO2 emissions an aim of the LEZ… There are lots of figures – limiting the number may make your messages clearer. This is a cross sectional survey looking at commuting behaviour inside and outside the Edinburgh LEZ. Key findings related to the mode usage, e.g. car, public transport inside and outside the LEZ zone with a small shift to active travel and public transport in the LEZ. I think this is a useful paper, looking beyond the air pollution impacts at travel behaviour. I’ve made some suggestions for the authors to consider which I hope are useful.

There needs to be a sentence on why the panel and community surveys. Also when it says “There was a clear differentiation in transport mode usage, with more people using the car alone for their commute outside the LEZ and more people using public transport inside the LEZ” make it clear whether this is prior to the LEZ or because of the LEZ. Main text: Although some of these points are addressed as limitations in the discussion I think they are important in interpreting the data, so further comment on these would improve the paper. A description of travel in the LEZ zone c.f. outside would be useful – prior to implementation, during the grace period and once implemented. Were there changes to other travel modes e.g. bus frequency, parking availability, no of cycle routes etc, which may have influenced the choices and change in modes reported. You also mention vehicle compliance, high for petrol cars, half for diesel, how did this change over time through the grace period inside the LEZ and around full implementation in 2024 and how did this compare with Edinburgh in general. Could the authors comment on how the survey accounts for the fact that the effects of the LEZ start during the grace period (start date in 2022). How would it have influenced the results. Also, the survey was 5 months after the 2024 start date which requires responders to think back to before LEZ. Was this in the grace period or maybe before that? Can you comment on the reliability of this data. The manuscript would benefit from more detail on the two survey’s - not only how representative they were of the wider population but also what were the reasons for having both community and panel results. Was it to compared strongly held opinions (community involvement) with more general opinions (panel)? Also, a statement on the degree to which the panel and community samples are comparable and support your results would be useful. For example: Fig 2 show differences in age….Fig 3 the panel and community are quite different, especially at the low SIMD deciles. Both have dominant decile 10. This seems unusual? It wasn’t clear to me why it was important to ask about “happiness yesterday” etc? I think this needs an explanation. How do you account for seasonal effects in your questions/data analysis. For example, if you survey in Oct/Nov for things like cycling now and compare this with what you did before LEZ (pre June 2024). It was confusing to use CO2 emissions as a metric and not include Nox emissions to assess the impact of the travel behaviour of the scheme? Was CO2 reduction a stated aim of the LEZ? In the commute modes analysis, I was also a bit surprised that bike/e-bike wasn’t chosen as it was relatively important and the differences between panel and community was large, which tells you something…your background talked a lot about active travel so it would seem to be a useful addition. Figure 8 – tiny numbers – are these results sound? Figure 12 – was CO2 emissions an aim of the LEZ… There are lots of figures – limiting the number may make your messages clearer. - Is the work clearly and accurately presented and does it cite the current literature? Yes - Is the study design appropriate and is the work technically sound? Yes - Are sufficient details of methods and analysis provided to allow replication by others? Yes - If applicable, is the statistical analysis and its interpretation appropriate? I cannot comment. A qualified statistician is required. - Are all the source data underlying the results available to ensure full reproducibility? Yes - Are the conclusions drawn adequately supported by the results? Yes Competing Interests: No competing interests were disclosed. Reviewer Expertise: I am an air pollution scientist and can provide general comments. I'd defer to a behavioural scientist/statististician for an assessment of the survey itself. CITE HOW TO CITE THIS REPORT Beevers S. Reviewer Report For: Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.15098.r36351) The direct URL for this report is: https://openresearch.nihr.ac.uk/articles/5-33/v1#referee-response-36351 https://openresearch.nihr.ac.uk/articles/5-33/v1#referee-response-36351 NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article. - Author Response 19 Jan 2026Will Mueller, Research Ave N, Institute of Occupational Medicine (IOM), Edinburgh, UK19 Jan 2026Author ResponseWe thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised. I think ... Continue reading We thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised. I think this is a useful paper, looking beyond the air pollution impacts at travel behaviour. I’ve made some suggestions for the authors to consider which I hope are useful.- We thank the reviewer for this positive feedback.

There needs to be a sentence on why the panel and community surveys.- We have clarified that the two recruitment modes were to increase the number of survey responses. Also when it says “There was a clear differentiation in transport mode usage, with more people using the car alone for their commute outside the LEZ and more people using public transport inside the LEZ” make it clear whether this is prior to the LEZ or because of the LEZ.- We have confirmed that these results refer to the post-enforcement period. Main text: Although some of these points are addressed as limitations in the discussion I think they are important in interpreting the data, so further comment on these would improve the paper. A description of travel in the LEZ zone c.f. outside would be useful – prior to implementation, during the grace period and once implemented. Were there changes to other travel modes e.g. bus frequency, parking availability, no of cycle routes etc, which may have influenced the choices and change in modes reported.- We agree this would be useful contextual information to add. Although we did not have available information on all of the changes that took place across different travel modes during the different LEZ implementation phases, we have added the following sentence in the discussion to address this point: The City of Edinburgh also increased parking fees (CEC, 2024d) and introduced new cycle lanes in the city centre (Walk Wheel Cycle Trust, 2024) only months before LEZ enforcement, potentially further discouraging private vehicle use. - We only had this information for 2022 for the whole City of Edinburgh, based on a SEPA study. We have clarified this particular sentence in the methods: Although 95% of petrol cars in Edinburgh were estimated to have been compliant at the time of LEZ implementation, only 50% of diesel cars met the required standard (CEC, 2023c). Could the authors comment on how the survey accounts for the fact that the effects of the LEZ start during the grace period (start date in 2022). How would it have influenced the results.- We agree this is an important point and had included the following excerpt in the discussion, noting the possible underestimation of LEZ impacts in our results: - Impacts may have been underestimated, given the LEZ was implemented two years earlier (without issuing non-compliance fees); individuals may have undertaken specific changes prior to enforcement, which would not have been captured through the analysis of travel before and after enforcement. Nevertheless, we did ask about the replacement of non-compliant vehicles, which applied to a minority of respondents: four of eight individuals commuting inside the LEZ reported upgrading their non-compliant vehicle. Survey questions related to behaviour changes due to knowledge of the LEZ and agreement on potential LEZ impacts did not specify ‘enforcement’, so it was not possible to distinguish effects from implementations versus enforcement in those responses. Also, the survey was 5 months after the 2024 start date which requires responders to think back to before LEZ. Was this in the grace period or maybe before that? Can you comment on the reliability of this data.- We thank the reviewer for noting this point and also considered this in the discussion with the below sentence. The actual survey wording was intentionally non-specific and referred to ‘before the LEZ enforcement,’ implying a comparison in the months before (i.e., during the grace period and not prior to implementation) and following enforcement (given the survey timing of 4-5 months afterward). - While self-reported travel behaviour has been shown to be reliable at the group level (Kelly et al., 2014), recall of pre-enforcement travel may have been less accurate, particularly if the start of LEZ enforcement was not a particularly salient event (Müggenburg, 2021). The manuscript would benefit from more detail on the two survey’s - not only how representative they were of the wider population but also what were the reasons for having both community and panel results. Was it to compared strongly held opinions (community involvement) with more general opinions (panel)?- We have noted in the methods that the two versions of the survey, based on different recruitment mechanisms, was to maximise the number of responses. Also, a statement on the degree to which the panel and community samples are comparable and support your results would be useful. For example: Fig 2 show differences in age….Fig 3 the panel and community are quite different, especially at the low SIMD deciles. Both have dominant decile 10. This seems unusual?- We have added in the strengths and limitations section a comparison of the study demographics in the panel and community surveys, in terms of age and deprivation (we did not collect ethnicity), compared to the larger Edinburgh population. - In both the panel and community surveys, the proportions of respondents were mainly distributed across ages 25-64, though with lower proportions of 18-24-year olds compared to Edinburgh, particularly in the community cohort (NRS, 2025). This demographic may have been less likely to receive/respond to online promotional content from the organisations involved in the study stakeholder group. More respondents were from the least deprived quintile according to the national SIMD rankings (panel: 31%; community: 40%), which is representative, but lower in fact, than the whole of Edinburgh (45%) (CEC, 2020). Therefore, our findings may be less reflective of younger Edinburgh residents living in more deprived areas. - The happiness and wellbeing questions were included to detect any differences between response subgroups and also to provide baseline information for potential future surveys. How do you account for seasonal effects in your questions/data analysis. For example, if you survey in Oct/Nov for things like cycling now and compare this with what you did before LEZ (pre June 2024).- This is an important point that we have now added to the discussion: - Travel behaviour may have differed by season between the current (i.e., October/November) and pre-enforcement (i.e., pre-June) timelines. Some respondents may have been less likely to engage in active travel during potentially cooler and darker conditions as reported in the ‘current’ time-period, the impact of which may have downplayed any positive associations following LEZ enforcement (Brainard et al., 2019). - Brainard, J., Cooke, R., Lane, K. and Salter, C., 2019. Age, sex and other correlates with active travel walking and cycling in England: Analysis of responses to the Active Lives Survey 2016/17. Preventive Medicine, 123, pp.225-231. It was confusing to use CO2 emissions as a metric and not include Nox emissions to assess the impact of the travel behaviour of the scheme? Was CO2 reduction a stated aim of the LEZ?- To clarify, we added the following underlined text in the methods section: - As an additional analysis, given the LEZ will contribute to Edinburgh’s 2030 Climate Strategy (CEC, 2021), we analysed the total commuting carbon emissions before and after enforcement for single modes of those commuting inside the LEZ. - CEC, 2021. 2030 Climate Strategy – Delivering a net zero, climate ready city. Last accessed 17 November 2025 from https://www.edinburgh.gov.uk/downloads/file/30783/2030-climate-strategy In the commute modes analysis, I was also a bit surprised that bike/e-bike wasn’t chosen as it was relatively important and the differences between panel and community was large, which tells you something…your background talked a lot about active travel so it would seem to be a useful addition.- We agree there were differences in the use of bike/e-bike in the community and panel surveys. In the inside/outside comparison, we examined the five most commonly reported travel modes, including those with multiple modes. ‘Bike’ was included in the community comparison, but not ‘e-bike’, the latter of which may have been reported alongside other modes such that it did not appear in the five most common. Including additional modes would have been a challenge to analyse with small samples sizes. Figure 8 – tiny numbers – are these results sound?- We have removed Figure 8 due to the small numbers involved. Figure 12 – was CO2 emissions an aim of the LEZ…- Please see our response three comments earlier. There are lots of figures – limiting the number may make your messages clearer.- We have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. Figure 8 and 16 have been removed. We thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised.Competing Interests: We declare no competing interests. Close I think this is a useful paper, looking beyond the air pollution impacts at travel behaviour. I’ve made some suggestions for the authors to consider which I hope are useful.- We thank the reviewer for this positive feedback.

There needs to be a sentence on why the panel and community surveys.- We have clarified that the two recruitment modes were to increase the number of survey responses. Also when it says “There was a clear differentiation in transport mode usage, with more people using the car alone for their commute outside the LEZ and more people using public transport inside the LEZ” make it clear whether this is prior to the LEZ or because of the LEZ.- We have confirmed that these results refer to the post-enforcement period. Main text: Although some of these points are addressed as limitations in the discussion I think they are important in interpreting the data, so further comment on these would improve the paper. A description of travel in the LEZ zone c.f. outside would be useful – prior to implementation, during the grace period and once implemented. Were there changes to other travel modes e.g. bus frequency, parking availability, no of cycle routes etc, which may have influenced the choices and change in modes reported.- We agree this would be useful contextual information to add. Although we did not have available information on all of the changes that took place across different travel modes during the different LEZ implementation phases, we have added the following sentence in the discussion to address this point: The City of Edinburgh also increased parking fees (CEC, 2024d) and introduced new cycle lanes in the city centre (Walk Wheel Cycle Trust, 2024) only months before LEZ enforcement, potentially further discouraging private vehicle use. - We only had this information for 2022 for the whole City of Edinburgh, based on a SEPA study. We have clarified this particular sentence in the methods: Although 95% of petrol cars in Edinburgh were estimated to have been compliant at the time of LEZ implementation, only 50% of diesel cars met the required standard (CEC, 2023c). Could the authors comment on how the survey accounts for the fact that the effects of the LEZ start during the grace period (start date in 2022). How would it have influenced the results.- We agree this is an important point and had included the following excerpt in the discussion, noting the possible underestimation of LEZ impacts in our results: - Impacts may have been underestimated, given the LEZ was implemented two years earlier (without issuing non-compliance fees); individuals may have undertaken specific changes prior to enforcement, which would not have been captured through the analysis of travel before and after enforcement. Nevertheless, we did ask about the replacement of non-compliant vehicles, which applied to a minority of respondents: four of eight individuals commuting inside the LEZ reported upgrading their non-compliant vehicle. Survey questions related to behaviour changes due to knowledge of the LEZ and agreement on potential LEZ impacts did not specify ‘enforcement’, so it was not possible to distinguish effects from implementations versus enforcement in those responses. Also, the survey was 5 months after the 2024 start date which requires responders to think back to before LEZ. Was this in the grace period or maybe before that? Can you comment on the reliability of this data.- We thank the reviewer for noting this point and also considered this in the discussion with the below sentence. The actual survey wording was intentionally non-specific and referred to ‘before the LEZ enforcement,’ implying a comparison in the months before (i.e., during the grace period and not prior to implementation) and following enforcement (given the survey timing of 4-5 months afterward). - While self-reported travel behaviour has been shown to be reliable at the group level (Kelly et al., 2014), recall of pre-enforcement travel may have been less accurate, particularly if the start of LEZ enforcement was not a particularly salient event (Müggenburg, 2021). The manuscript would benefit from more detail on the two survey’s - not only how representative they were of the wider population but also what were the reasons for having both community and panel results. Was it to compared strongly held opinions (community involvement) with more general opinions (panel)?- We have noted in the methods that the two versions of the survey, based on different recruitment mechanisms, was to maximise the number of responses. Also, a statement on the degree to which the panel and community samples are comparable and support your results would be useful. For example: Fig 2 show differences in age….Fig 3 the panel and community are quite different, especially at the low SIMD deciles. Both have dominant decile 10. This seems unusual?- We have added in the strengths and limitations section a comparison of the study demographics in the panel and community surveys, in terms of age and deprivation (we did not collect ethnicity), compared to the larger Edinburgh population. - In both the panel and community surveys, the proportions of respondents were mainly distributed across ages 25-64, though with lower proportions of 18-24-year olds compared to Edinburgh, particularly in the community cohort (NRS, 2025). This demographic may have been less likely to receive/respond to online promotional content from the organisations involved in the study stakeholder group. More respondents were from the least deprived quintile according to the national SIMD rankings (panel: 31%; community: 40%), which is representative, but lower in fact, than the whole of Edinburgh (45%) (CEC, 2020). Therefore, our findings may be less reflective of younger Edinburgh residents living in more deprived areas. - The happiness and wellbeing questions were included to detect any differences between response subgroups and also to provide baseline information for potential future surveys. How do you account for seasonal effects in your questions/data analysis. For example, if you survey in Oct/Nov for things like cycling now and compare this with what you did before LEZ (pre June 2024).- This is an important point that we have now added to the discussion: - Travel behaviour may have differed by season between the current (i.e., October/November) and pre-enforcement (i.e., pre-June) timelines. Some respondents may have been less likely to engage in active travel during potentially cooler and darker conditions as reported in the ‘current’ time-period, the impact of which may have downplayed any positive associations following LEZ enforcement (Brainard et al., 2019). - Brainard, J., Cooke, R., Lane, K. and Salter, C., 2019. Age, sex and other correlates with active travel walking and cycling in England: Analysis of responses to the Active Lives Survey 2016/17. Preventive Medicine, 123, pp.225-231. It was confusing to use CO2 emissions as a metric and not include Nox emissions to assess the impact of the travel behaviour of the scheme? Was CO2 reduction a stated aim of the LEZ?- To clarify, we added the following underlined text in the methods section: - As an additional analysis, given the LEZ will contribute to Edinburgh’s 2030 Climate Strategy (CEC, 2021), we analysed the total commuting carbon emissions before and after enforcement for single modes of those commuting inside the LEZ. - CEC, 2021. 2030 Climate Strategy – Delivering a net zero, climate ready city. Last accessed 17 November 2025 from https://www.edinburgh.gov.uk/downloads/file/30783/2030-climate-strategy In the commute modes analysis, I was also a bit surprised that bike/e-bike wasn’t chosen as it was relatively important and the differences between panel and community was large, which tells you something…your background talked a lot about active travel so it would seem to be a useful addition.- We agree there were differences in the use of bike/e-bike in the community and panel surveys. In the inside/outside comparison, we examined the five most commonly reported travel modes, including those with multiple modes. ‘Bike’ was included in the community comparison, but not ‘e-bike’, the latter of which may have been reported alongside other modes such that it did not appear in the five most common. Including additional modes would have been a challenge to analyse with small samples sizes. Figure 8 – tiny numbers – are these results sound?- We have removed Figure 8 due to the small numbers involved. Figure 12 – was CO2 emissions an aim of the LEZ…- Please see our response three comments earlier. There are lots of figures – limiting the number may make your messages clearer.- We have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. Figure 8 and 16 have been removed. COMMENTS ON THIS REPORT - Author Response 19 Jan 2026Will Mueller, Research Ave N, Institute of Occupational Medicine (IOM), Edinburgh, UK19 Jan 2026Author ResponseWe thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised. I think ... Continue reading We thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised. I think this is a useful paper, looking beyond the air pollution impacts at travel behaviour. I’ve made some suggestions for the authors to consider which I hope are useful.- We thank the reviewer for this positive feedback.

There needs to be a sentence on why the panel and community surveys.- We have clarified that the two recruitment modes were to increase the number of survey responses. Also when it says “There was a clear differentiation in transport mode usage, with more people using the car alone for their commute outside the LEZ and more people using public transport inside the LEZ” make it clear whether this is prior to the LEZ or because of the LEZ.- We have confirmed that these results refer to the post-enforcement period. Main text: Although some of these points are addressed as limitations in the discussion I think they are important in interpreting the data, so further comment on these would improve the paper. A description of travel in the LEZ zone c.f. outside would be useful – prior to implementation, during the grace period and once implemented. Were there changes to other travel modes e.g. bus frequency, parking availability, no of cycle routes etc, which may have influenced the choices and change in modes reported.- We agree this would be useful contextual information to add. Although we did not have available information on all of the changes that took place across different travel modes during the different LEZ implementation phases, we have added the following sentence in the discussion to address this point: The City of Edinburgh also increased parking fees (CEC, 2024d) and introduced new cycle lanes in the city centre (Walk Wheel Cycle Trust, 2024) only months before LEZ enforcement, potentially further discouraging private vehicle use. - We only had this information for 2022 for the whole City of Edinburgh, based on a SEPA study. We have clarified this particular sentence in the methods: Although 95% of petrol cars in Edinburgh were estimated to have been compliant at the time of LEZ implementation, only 50% of diesel cars met the required standard (CEC, 2023c). Could the authors comment on how the survey accounts for the fact that the effects of the LEZ start during the grace period (start date in 2022). How would it have influenced the results.- We agree this is an important point and had included the following excerpt in the discussion, noting the possible underestimation of LEZ impacts in our results: - Impacts may have been underestimated, given the LEZ was implemented two years earlier (without issuing non-compliance fees); individuals may have undertaken specific changes prior to enforcement, which would not have been captured through the analysis of travel before and after enforcement. Nevertheless, we did ask about the replacement of non-compliant vehicles, which applied to a minority of respondents: four of eight individuals commuting inside the LEZ reported upgrading their non-compliant vehicle. Survey questions related to behaviour changes due to knowledge of the LEZ and agreement on potential LEZ impacts did not specify ‘enforcement’, so it was not possible to distinguish effects from implementations versus enforcement in those responses. Also, the survey was 5 months after the 2024 start date which requires responders to think back to before LEZ. Was this in the grace period or maybe before that? Can you comment on the reliability of this data.- We thank the reviewer for noting this point and also considered this in the discussion with the below sentence. The actual survey wording was intentionally non-specific and referred to ‘before the LEZ enforcement,’ implying a comparison in the months before (i.e., during the grace period and not prior to implementation) and following enforcement (given the survey timing of 4-5 months afterward). - While self-reported travel behaviour has been shown to be reliable at the group level (Kelly et al., 2014), recall of pre-enforcement travel may have been less accurate, particularly if the start of LEZ enforcement was not a particularly salient event (Müggenburg, 2021). The manuscript would benefit from more detail on the two survey’s - not only how representative they were of the wider population but also what were the reasons for having both community and panel results. Was it to compared strongly held opinions (community involvement) with more general opinions (panel)?- We have noted in the methods that the two versions of the survey, based on different recruitment mechanisms, was to maximise the number of responses. Also, a statement on the degree to which the panel and community samples are comparable and support your results would be useful. For example: Fig 2 show differences in age….Fig 3 the panel and community are quite different, especially at the low SIMD deciles. Both have dominant decile 10. This seems unusual?- We have added in the strengths and limitations section a comparison of the study demographics in the panel and community surveys, in terms of age and deprivation (we did not collect ethnicity), compared to the larger Edinburgh population. - In both the panel and community surveys, the proportions of respondents were mainly distributed across ages 25-64, though with lower proportions of 18-24-year olds compared to Edinburgh, particularly in the community cohort (NRS, 2025). This demographic may have been less likely to receive/respond to online promotional content from the organisations involved in the study stakeholder group. More respondents were from the least deprived quintile according to the national SIMD rankings (panel: 31%; community: 40%), which is representative, but lower in fact, than the whole of Edinburgh (45%) (CEC, 2020). Therefore, our findings may be less reflective of younger Edinburgh residents living in more deprived areas. - The happiness and wellbeing questions were included to detect any differences between response subgroups and also to provide baseline information for potential future surveys. How do you account for seasonal effects in your questions/data analysis. For example, if you survey in Oct/Nov for things like cycling now and compare this with what you did before LEZ (pre June 2024).- This is an important point that we have now added to the discussion: - Travel behaviour may have differed by season between the current (i.e., October/November) and pre-enforcement (i.e., pre-June) timelines. Some respondents may have been less likely to engage in active travel during potentially cooler and darker conditions as reported in the ‘current’ time-period, the impact of which may have downplayed any positive associations following LEZ enforcement (Brainard et al., 2019). - Brainard, J., Cooke, R., Lane, K. and Salter, C., 2019. Age, sex and other correlates with active travel walking and cycling in England: Analysis of responses to the Active Lives Survey 2016/17. Preventive Medicine, 123, pp.225-231. It was confusing to use CO2 emissions as a metric and not include Nox emissions to assess the impact of the travel behaviour of the scheme? Was CO2 reduction a stated aim of the LEZ?- To clarify, we added the following underlined text in the methods section: - As an additional analysis, given the LEZ will contribute to Edinburgh’s 2030 Climate Strategy (CEC, 2021), we analysed the total commuting carbon emissions before and after enforcement for single modes of those commuting inside the LEZ. - CEC, 2021. 2030 Climate Strategy – Delivering a net zero, climate ready city. Last accessed 17 November 2025 from https://www.edinburgh.gov.uk/downloads/file/30783/2030-climate-strategy In the commute modes analysis, I was also a bit surprised that bike/e-bike wasn’t chosen as it was relatively important and the differences between panel and community was large, which tells you something…your background talked a lot about active travel so it would seem to be a useful addition.- We agree there were differences in the use of bike/e-bike in the community and panel surveys. In the inside/outside comparison, we examined the five most commonly reported travel modes, including those with multiple modes. ‘Bike’ was included in the community comparison, but not ‘e-bike’, the latter of which may have been reported alongside other modes such that it did not appear in the five most common. Including additional modes would have been a challenge to analyse with small samples sizes. Figure 8 – tiny numbers – are these results sound?- We have removed Figure 8 due to the small numbers involved. Figure 12 – was CO2 emissions an aim of the LEZ…- Please see our response three comments earlier. There are lots of figures – limiting the number may make your messages clearer.- We have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. Figure 8 and 16 have been removed. We thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised.Competing Interests: We declare no competing interests. Close I think this is a useful paper, looking beyond the air pollution impacts at travel behaviour. I’ve made some suggestions for the authors to consider which I hope are useful.- We thank the reviewer for this positive feedback.

There needs to be a sentence on why the panel and community surveys.- We have clarified that the two recruitment modes were to increase the number of survey responses. Also when it says “There was a clear differentiation in transport mode usage, with more people using the car alone for their commute outside the LEZ and more people using public transport inside the LEZ” make it clear whether this is prior to the LEZ or because of the LEZ.- We have confirmed that these results refer to the post-enforcement period. Main text: Although some of these points are addressed as limitations in the discussion I think they are important in interpreting the data, so further comment on these would improve the paper. A description of travel in the LEZ zone c.f. outside would be useful – prior to implementation, during the grace period and once implemented. Were there changes to other travel modes e.g. bus frequency, parking availability, no of cycle routes etc, which may have influenced the choices and change in modes reported.- We agree this would be useful contextual information to add. Although we did not have available information on all of the changes that took place across different travel modes during the different LEZ implementation phases, we have added the following sentence in the discussion to address this point: The City of Edinburgh also increased parking fees (CEC, 2024d) and introduced new cycle lanes in the city centre (Walk Wheel Cycle Trust, 2024) only months before LEZ enforcement, potentially further discouraging private vehicle use. - We only had this information for 2022 for the whole City of Edinburgh, based on a SEPA study. We have clarified this particular sentence in the methods: Although 95% of petrol cars in Edinburgh were estimated to have been compliant at the time of LEZ implementation, only 50% of diesel cars met the required standard (CEC, 2023c). Could the authors comment on how the survey accounts for the fact that the effects of the LEZ start during the grace period (start date in 2022). How would it have influenced the results.- We agree this is an important point and had included the following excerpt in the discussion, noting the possible underestimation of LEZ impacts in our results: - Impacts may have been underestimated, given the LEZ was implemented two years earlier (without issuing non-compliance fees); individuals may have undertaken specific changes prior to enforcement, which would not have been captured through the analysis of travel before and after enforcement. Nevertheless, we did ask about the replacement of non-compliant vehicles, which applied to a minority of respondents: four of eight individuals commuting inside the LEZ reported upgrading their non-compliant vehicle. Survey questions related to behaviour changes due to knowledge of the LEZ and agreement on potential LEZ impacts did not specify ‘enforcement’, so it was not possible to distinguish effects from implementations versus enforcement in those responses. Also, the survey was 5 months after the 2024 start date which requires responders to think back to before LEZ. Was this in the grace period or maybe before that? Can you comment on the reliability of this data.- We thank the reviewer for noting this point and also considered this in the discussion with the below sentence. The actual survey wording was intentionally non-specific and referred to ‘before the LEZ enforcement,’ implying a comparison in the months before (i.e., during the grace period and not prior to implementation) and following enforcement (given the survey timing of 4-5 months afterward). - While self-reported travel behaviour has been shown to be reliable at the group level (Kelly et al., 2014), recall of pre-enforcement travel may have been less accurate, particularly if the start of LEZ enforcement was not a particularly salient event (Müggenburg, 2021). The manuscript would benefit from more detail on the two survey’s - not only how representative they were of the wider population but also what were the reasons for having both community and panel results. Was it to compared strongly held opinions (community involvement) with more general opinions (panel)?- We have noted in the methods that the two versions of the survey, based on different recruitment mechanisms, was to maximise the number of responses. Also, a statement on the degree to which the panel and community samples are comparable and support your results would be useful. For example: Fig 2 show differences in age….Fig 3 the panel and community are quite different, especially at the low SIMD deciles. Both have dominant decile 10. This seems unusual?- We have added in the strengths and limitations section a comparison of the study demographics in the panel and community surveys, in terms of age and deprivation (we did not collect ethnicity), compared to the larger Edinburgh population. - In both the panel and community surveys, the proportions of respondents were mainly distributed across ages 25-64, though with lower proportions of 18-24-year olds compared to Edinburgh, particularly in the community cohort (NRS, 2025). This demographic may have been less likely to receive/respond to online promotional content from the organisations involved in the study stakeholder group. More respondents were from the least deprived quintile according to the national SIMD rankings (panel: 31%; community: 40%), which is representative, but lower in fact, than the whole of Edinburgh (45%) (CEC, 2020). Therefore, our findings may be less reflective of younger Edinburgh residents living in more deprived areas. - The happiness and wellbeing questions were included to detect any differences between response subgroups and also to provide baseline information for potential future surveys. How do you account for seasonal effects in your questions/data analysis. For example, if you survey in Oct/Nov for things like cycling now and compare this with what you did before LEZ (pre June 2024).- This is an important point that we have now added to the discussion: - Travel behaviour may have differed by season between the current (i.e., October/November) and pre-enforcement (i.e., pre-June) timelines. Some respondents may have been less likely to engage in active travel during potentially cooler and darker conditions as reported in the ‘current’ time-period, the impact of which may have downplayed any positive associations following LEZ enforcement (Brainard et al., 2019). - Brainard, J., Cooke, R., Lane, K. and Salter, C., 2019. Age, sex and other correlates with active travel walking and cycling in England: Analysis of responses to the Active Lives Survey 2016/17. Preventive Medicine, 123, pp.225-231. It was confusing to use CO2 emissions as a metric and not include Nox emissions to assess the impact of the travel behaviour of the scheme? Was CO2 reduction a stated aim of the LEZ?- To clarify, we added the following underlined text in the methods section: - As an additional analysis, given the LEZ will contribute to Edinburgh’s 2030 Climate Strategy (CEC, 2021), we analysed the total commuting carbon emissions before and after enforcement for single modes of those commuting inside the LEZ. - CEC, 2021. 2030 Climate Strategy – Delivering a net zero, climate ready city. Last accessed 17 November 2025 from https://www.edinburgh.gov.uk/downloads/file/30783/2030-climate-strategy In the commute modes analysis, I was also a bit surprised that bike/e-bike wasn’t chosen as it was relatively important and the differences between panel and community was large, which tells you something…your background talked a lot about active travel so it would seem to be a useful addition.- We agree there were differences in the use of bike/e-bike in the community and panel surveys. In the inside/outside comparison, we examined the five most commonly reported travel modes, including those with multiple modes. ‘Bike’ was included in the community comparison, but not ‘e-bike’, the latter of which may have been reported alongside other modes such that it did not appear in the five most common. Including additional modes would have been a challenge to analyse with small samples sizes. Figure 8 – tiny numbers – are these results sound?- We have removed Figure 8 due to the small numbers involved. Figure 12 – was CO2 emissions an aim of the LEZ…- Please see our response three comments earlier. There are lots of figures – limiting the number may make your messages clearer.- We have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. Figure 8 and 16 have been removed. Views 0 How to cite this report: McEachan R. Reviewer Report For: Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.15098.r35293) The direct URL for this report is: https://openresearch.nihr.ac.uk/articles/5-33/v1#referee-response-35293 https://openresearch.nihr.ac.uk/articles/5-33/v1#referee-response-35293 NOTE: it is important to ensure the information in square brackets after the title is included in this citation. Reviewer Report 03 Jun 2025 Approved with Reservations VIEWS 0 The authors report a cross sectional survey reporting changes in travel behaviour and perceptions amongst residents of a Scottish city following the enforcement of a low emission zone. The paper is well reported and comprehensive in methods, results ... Continue reading I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. Close The paper is well reported and comprehensive in methods, results ... Continue reading The authors report a cross sectional survey reporting changes in travel behaviour and perceptions amongst residents of a Scottish city following the enforcement of a low emission zone. The paper is well reported and comprehensive in methods, results and discussion. The strengths and limitations are clearly articulated and appropriate. I have made some suggestions which I feel would further improve the manuscript. The paper is well reported and comprehensive in methods, results and discussion. The strengths and limitations are clearly articulated and appropriate. I have made some suggestions which I feel would further improve the manuscript. - The introduction contains relevant material, but it would be good if the authors could clarify uncertainties and the novel contribution of the current study – what research gap is it trying to fill? - It would be useful if the authors could comment on the representativeness of both the community and panel sample in relation to general demographics of residents in Edinburgh (e.g. age, ethnicity, IMD indices). In the limitations section any major differences in sample characteristics should be noted, along with implications for interpretation. - The reporting is very comprehensive, but there are a lot of figures and tables, which can make it hard for the reader to find key material. For example could Figures 1-3 be combined into one table describing characteristics of the sample? - Some of the visualisations are reporting very small sample sizes (e.g. figure 8 – N=2; Figure 11, Figure 16). I’m not sure how useful these are, as a rule of thumb consider suppressing small sample sizes. - Is the work clearly and accurately presented and does it cite the current literature? Yes - Is the study design appropriate and is the work technically sound? Yes - Are sufficient details of methods and analysis provided to allow replication by others? Yes - If applicable, is the statistical analysis and its interpretation appropriate? Yes - Are all the source data underlying the results available to ensure full reproducibility? Yes - Are the conclusions drawn adequately supported by the results? Yes Competing Interests: No competing interests were disclosed. Reviewer Expertise: Complex intervention development and evaluation; evaluation of clean air zones; environmental determinants of health; cohort studies. CITE HOW TO CITE THIS REPORT McEachan R. Reviewer Report For: Travel behaviour and Edinburgh’s Low Emission Zone: a cross-sectional survey [version 2; peer review: 1 approved, 1 approved with reservations]. NIHR Open Res 2026, 5:33 (https://doi.org/10.3310/nihropenres.15098.r35293) The direct URL for this report is: https://openresearch.nihr.ac.uk/articles/5-33/v1#referee-response-35293 https://openresearch.nihr.ac.uk/articles/5-33/v1#referee-response-35293 NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article. - Author Response 19 Jan 2026Will Mueller, Research Ave N, Institute of Occupational Medicine (IOM), Edinburgh, UK19 Jan 2026Author ResponseWe thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised. 1.The introduction ... Continue reading We thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised. 1.The introduction contains relevant material, but it would be good if the authors could clarify uncertainties and the novel contribution of the current study – what research gap is it trying to fill?- We have added to the background section that the study is to extend the limited evidence base on LEZs and active travel, which at present is mainly attributed to the London Ultra LEZ. - We have added in the strengths and limitations section a comparison of the study demographics, in terms of age and deprivation (we did not collect ethnicity), compared to the larger Edinburgh population. - We have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. - We have removed Figures 8 and 16, which had small sample sizes. The others we have retained as they present useful results from our study. Some of the figures do show categories with fewer than 5 respondents, but we have included these as is for completion. We thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised.Competing Interests: I declare no competing interests. Close 1.The introduction contains relevant material, but it would be good if the authors could clarify uncertainties and the novel contribution of the current study – what research gap is it trying to fill?- We have added to the background section that the study is to extend the limited evidence base on LEZs and active travel, which at present is mainly attributed to the London Ultra LEZ. - We have added in the strengths and limitations section a comparison of the study demographics, in terms of age and deprivation (we did not collect ethnicity), compared to the larger Edinburgh population. - We have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. - We have removed Figures 8 and 16, which had small sample sizes. The others we have retained as they present useful results from our study. Some of the figures do show categories with fewer than 5 respondents, but we have included these as is for completion. COMMENTS ON THIS REPORT - Author Response 19 Jan 2026Will Mueller, Research Ave N, Institute of Occupational Medicine (IOM), Edinburgh, UK19 Jan 2026Author ResponseWe thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised. 1.The introduction ... Continue reading We thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised. 1.The introduction contains relevant material, but it would be good if the authors could clarify uncertainties and the novel contribution of the current study – what research gap is it trying to fill?- We have added to the background section that the study is to extend the limited evidence base on LEZs and active travel, which at present is mainly attributed to the London Ultra LEZ. - We have added in the strengths and limitations section a comparison of the study demographics, in terms of age and deprivation (we did not collect ethnicity), compared to the larger Edinburgh population. - We have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. - We have removed Figures 8 and 16, which had small sample sizes. The others we have retained as they present useful results from our study. Some of the figures do show categories with fewer than 5 respondents, but we have included these as is for completion. We thank the reviewer for their thoughtful and helpful input. We have responded below to the individual comments and hope we have sufficiently addressed all points raised.Competing Interests: I declare no competing interests. Close 1.The introduction contains relevant material, but it would be good if the authors could clarify uncertainties and the novel contribution of the current study – what research gap is it trying to fill?- We have added to the background section that the study is to extend the limited evidence base on LEZs and active travel, which at present is mainly attributed to the London Ultra LEZ. - We have added in the strengths and limitations section a comparison of the study demographics, in terms of age and deprivation (we did not collect ethnicity), compared to the larger Edinburgh population. - We have combined the data from Figures 2 and 3 into what is now Table 1 and have replaced Figure 4 with text. - We have removed Figures 8 and 16, which had small sample sizes. The others we have retained as they present useful results from our study. Some of the figures do show categories with fewer than 5 respondents, but we have included these as is for completion. Alongside their report, reviewers assign a status to the article: - Approved - Approved with reservations - Not approved | Invited Reviewers | || |---|---|---| | 1 | 2 | | | Version 2 (revision) 19 Jan 26 | read | | | Version 1 14 Apr 25 | read | read | Sign up for content alerts You are now signed up to receive this alert Alongside their report, reviewers assign a status to the article: Approved - the paper is scientifically sound in its current form and only minor, if any, improvements are suggested Approved with reservations - A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit. Not approved - fundamental flaws in the paper seriously undermine the findings and conclusions Provide sufficient details of any financial or non-financial competing interests to enable users to assess whether your comments might lead a reasonable person to question your impartiality. Consider the following examples, but note that this is not an exhaustive list: Examples of 'Non-Financial Competing Interests' - Within the past 4 years, you have held joint grants, published or collaborated with any of the authors of the selected paper. - You have a close personal relationship (e.g. parent, spouse, sibling, or domestic partner) with any of the authors. - You are a close professional associate of any of the authors (e.g. scientific mentor, recent student). - You work at the same institute as any of the authors. - You hope/expect to benefit (e.g. favour or employment) as a result of your submission. - You are an Editor for the journal in which the article is published. Examples of 'Financial Competing Interests' - You expect to receive, or in the past 4 years have received, any of the following from any commercial organisation that may gain financially from your submission: a salary, fees, funding, reimbursements. - You expect to receive, or in the past 4 years have received, shared grant support or other funding with any of the authors. - You hold, or are currently applying for, any patents or significant stocks/shares relating to the subject matter of the paper you are commenting on. Sign up for content alerts and receive a weekly or monthly email with all newly published articles Register with NIHR Open Research Already registered? Sign in close Error If you are a previous or current NIHR award holder, sign up for information about developments, publishing and publications from NIHR Open Research. We'll keep you updated on any major new updates to NIHR Open Research Sign In If you've forgotten your password, please enter your email address below and we'll send you instructions on how to reset your password. Email us for further assistance. The email address should be the one you originally registered with F1000. Email address not valid, please try again You registered with F1000 via Google, so we cannot reset your password. To sign in, please click here. If you still need help with your Google account password, please click here. You registered with F1000 via Facebook, so we cannot reset your password. To sign in, please click here. If you still need help with your Facebook account password, please click here. Code not correct, please try again Server error, please try again. If your email address is registered with us, we will email you instructions to reset your password. If you think you should have received this email but it has not arrived, please check your spam filters and/or contact for further assistance. Please wait...