[How to improve active mobility in São Paulo, Brazil? Survey with leaders of nongovernmental organizations and public and private sector managers]. / Como melhorar a mobilidade ativa em São Paulo, Brasil? Inquérito com lideranças de organizações não governamentais e com gestores públicos e privados.

This study aimed to describe a quantitative survey conducted with leaders to investigate effective and feasible actions that can be evaluated in computational models to inform policies to promote active mobility based in the city of São Paulo, Brazil. In 2022, an online survey was conducted during the Health Survey in São Paulo (Physical Activity and Environment study), which is monitored by representatives of nongovernmental organizations and public and private sector managers. A questionnaire was elaborated with three questions with 13 alternative answers about actions to promote walking and/or cycling. Leaders should select up to three alternatives based on their potential regarding: (1) effectiveness; (2) feasibility or ease of implementation; and (3) desire to verify tests in computational models to inform policies. The survey was answered by 18 leaders from 16 institutions, comprising 13 (72%) women and 12 (67%) representatives of the third sector, whose average age was 48 years and all had complete higher education. Reducing the speed of motor vehicles was the most cited option in all three questions. Other actions mentioned refer to controlling the traffic of vehicles in central areas, improving pedestrian safety, reducing the distances between homes and places of employment, conducting educational campaigns, and expanding and enhancing structures such as bicycle lanes and sidewalks. The results are relevant to support evidence-based decision-making in public management and to provide subsidies for the development of computational models with a view to promoting active mobility.

Este estudo teve como objetivo descrever um inquérito quantitativo realizado com lideranças para investigar ações efetivas, viáveis e que podem ser testadas em modelos computacionais para informar políticas de promoção da mobilidade ativa, tendo como base a cidade de São Paulo, Brasil. Em 2022, foi realizado um inquérito online no contexto da pesquisa de Atividade Física e Ambiente do Inquérito de Saúde de São Paulo, acompanhada por representantes de organizações não governamentais, gestores públicos e de entidades privadas. Foi elaborado questionário com três perguntas com 13 alternativas de respostas sobre ações para promoção da caminhada ou uso de bicicleta. As lideranças deveriam selecionar até três alternativas a partir de seu potencial em termos de (1) efetividade; (2) viabilidade ou facilidade de implementação; e (3) desejo de realizar testes em modelos computacionais para informar políticas. O inquérito foi respondido por 18 lideranças de 16 instituições, sendo 13 (72%) mulheres e 12 (67%) representantes do terceiro setor, cuja média de idade era 48 anos, todos com nível superior de escolaridade. A redução da velocidade dos veículos motorizados foi a opção mais citada nas três questões. Outras ações citadas referem-se ao controle de circulação de veículos em regiões centrais, à segurança de pedestres, à diminuição das distâncias entre residências e locais de emprego, às campanhas educativas e à ampliação e melhoria de estruturas como ciclovias e calçadas. Os resultados são relevantes para apoiar a tomada de decisões baseadas em evidências na gestão pública e oferecer subsídios para a elaboração de modelos computacionais com vistas à promoção da mobilidade ativa.

Este estudio tuvo como objetivo presentar una encuesta cuantitativa realizada con líderes para investigar las acciones efectivas, viables y que puedan probarse en modelos informáticos para orientar las políticas que promuevan la movilidad activa en la ciudad de São Paulo, Brasil. En 2022 se realizó una encuesta en línea en el contexto de la Encuesta de Salud de São Paulo (Actividad Física y Medio Ambiente), que es monitoreada por representantes de organizaciones no gubernamentales, gestores públicos y entidades privadas. Se elaboró un cuestionario de tres preguntas con 13 respuestas alternativas sobre acciones para promover la caminata o el uso de la bicicleta. Los líderes podían seleccionar hasta tres alternativas en función de su potencial en términos de (1) efectividad; (2) viabilidad o facilidad de implementación; y (3) deseo de verificar las pruebas en modelos informáticos para orientar las políticas. La encuesta fue respondida por 18 líderes de 16 instituciones; de los cuales 13 (72%) eran mujeres y 12 (67%) representaban el tercer sector; la edad promedio de ellos fue de 48 años y todos contaban con educación superior. Reducir la velocidad de los vehículos de motor fue la opción más citada en las tres preguntas. Otras acciones mencionadas se refieren al control de la circulación de vehículos en las regiones centrales, la seguridad de los peatones, la reducción de las distancias entre los hogares y los lugares de trabajo, las campañas educativas y la expansión y mejora de estructuras como carriles bici y aceras. Los resultados son relevantes para apoyar la toma de decisiones basada en la evidencia en la gestión pública y ofrecer subsidios para la elaboración de modelos computacionales destinados a promover la movilidad activa.

Uncovering physical activity trade-offs in transportation policy: A spatial agent-based model of Bogotá, Colombia.

BACKGROUND: Transportation policies can impact health outcomes while simultaneously promoting social equity and environmental sustainability. We developed an agent-based model (ABM) to simulate the impacts of fare subsidies and congestion taxes on commuter decision-making and travel patterns. We report effects on mode share, travel time and transport-related physical activity (PA), including the variability of effects by socioeconomic strata (SES), and the trade-offs that may need to be considered in the implementation of these policies in a context with high levels of necessity-based physical activity. METHODS: The ABM design was informed by local stakeholder engagement. The demographic and spatial characteristics of the in-silico city, and its residents, were informed by local surveys and empirical studies. We used ridership and travel time data from the 2019 Bogotá Household Travel Survey to calibrate and validate the model by SES. We then explored the impacts of fare subsidy and congestion tax policy scenarios. RESULTS: Our model reproduced commuting patterns observed in Bogotá, including substantial necessity-based walking for transportation. At the city-level, congestion taxes fractionally reduced car use, including among mid-to-high SES groups but not among low SES commuters. Neither travel times nor physical activity levels were impacted at the city level or by SES. Comparatively, fare subsidies promoted city-level public transportation (PT) ridership, particularly under a 'free-fare' scenario, largely through reductions in walking trips. 'Free fare' policies also led to a large reduction in very long walking times and an overall reduction in the commuting-based attainment of physical activity guidelines. Differential effects were observed by SES, with free fares promoting PT ridership primarily among low-and-middle SES groups. These shifts to PT reduced median walking times among all SES groups, particularly low-SES groups. Moreover, the proportion of low-to-mid SES commuters meeting weekly physical activity recommendations decreased under the 'freefare' policy, with no change observed among high-SES groups. CONCLUSIONS: Transport policies can differentially impact SES-level disparities in necessity-based walking and travel times. Understanding these impacts is critical in shaping transportation policies that balance the dual aims of reducing SES-level disparities in travel time (and time poverty) and the promotion of choice-based physical activity.

Integrative Assessment of Cardiopulmonary Fitness Using Cardiopulmonary Exercise Test With Supine Bicycle Echocardiography in Patients Presenting Dyspnea.

BACKGROUND: Cardiopulmonary exercise test (CPET) with supine bicycle echocardiography (SBE) enables comprehensive physiologic assessment during exercise. We characterized cardiopulmonary fitness by integrating CPET-SBE parameters and evaluated its prognostic value in patients presenting with dyspnea. METHODS AND RESULTS: We retrospectively reviewed 473 consecutive patients who underwent CPET-SBE for dyspnea evaluation. A dimensionality reduction process was applied, transforming 24 clinical and CPET-SBE parameters into a 2-dimensional feature map, followed by patient clustering based on the data distribution. Clinical and exercise features were compared among the clusters in addition to the 5-year risk of clinical outcome (a composite of cardiovascular death and heart failure hospitalization). Maximum exercise effort (R >1) was achieved in 95% of cases. Through dimensionality reduction, 3 patient clusters were derived: Group 1 (n=157), 2 (n=104), and 3 (n=212). Median age and female proportion increased from Group 1 to 2, and 3, although resting echocardiography parameters showed no significant abnormalities among the groups. There was a worsening trend in the exercise response from Group 1 to 2 and 3, including left ventricular diastolic function, oxygen consumption, and ventilatory efficiency. During follow-up (median 6.0 [1.6-10.4] years), clinical outcome increased from Group 1 to 2 and 3 (5-year rate 3.7% versus 7.0% versus 13.0%, respectively; log-rank P=0.02), with higher risk in Group 2 (hazard ratio, 1.94 [95% CI, 0.52-7.22]) and Group 3 (3.92 [1.34-11.42]) compared with Group 1. CONCLUSIONS: Comprehensive evaluation using CPET-SBE can reveal distinct characteristics of cardiopulmonary fitness in patients presenting with dyspnea, potentially enhancing outcome prediction.

An Assessment of Sikh Turban's Head Protection in Bicycle Incident Scenarios.

Due to religious tenets, Sikh population wear turbans and are exempted from wearing helmets in several countries. However, the extent of protection provided by turbans against head injuries during head impacts remains untested. One aim of this study was to provide the first-series data of turbans' protective performance under impact conditions that are representative of real-world bicycle incidents and compare it with the performance of bicycle helmets. Another aim was to suggest potential ways for improving turban's protective performance. We tested five different turbans, distinguished by two wrapping styles and two fabric materials with a size variation in one of the styles. A Hybrid III headform fitted with the turban was dropped onto a 45 degrees anvil at 6.3 m/s and head accelerations were measured. We found large difference in the performance of different turbans, with up to 59% difference in peak translational acceleration, 85% in peak rotational acceleration, and 45% in peak rotational velocity between the best and worst performing turbans. For the same turban, impact on the left and right sides of the head produced very different head kinematics, showing the effects of turban layering. Compared to unprotected head impacts, turbans considerably reduce head injury metrics. However, turbans produced higher values of peak linear and rotational accelerations in front and left impacts than bicycle helmets, except from one turban which produced lower peak head kinematics values in left impacts. In addition, turbans produced peak rotational velocities comparable with bicycle helmets, except from one turban which produced higher values. The impact locations tested here were covered with thick layers of turbans and they were impacted against flat anvils. Turbans may not provide much protection if impacts occur at regions covered with limited amount of fabric or if the impact is against non-flat anvils, which remain untested. Our analysis shows that turbans can be easily compressed and bottom out creating spikes in the headform's translational acceleration. In addition, the high friction between the turban and anvil surface leads to higher tangential force generating more rotational motion. Hence, in addition to improving the coverage of the head, particularly in the crown and rear locations, we propose two directions for turban improvement: (i) adding deformable materials within the turban layers to increase the impact duration and reduce the risk of bottoming out; (ii) reducing the friction between turban layers to reduce the transmission of rotational motion to the head. Overall, the study assessed Turbans' protection in cyclist head collisions, with a vision that the results of this study can guide further necessary improvements for advanced head protection for the Sikh community.

Evaluation of the "Build your bike!" pilot project by and for disadvantaged youth: A school-based intervention to promote active mobility / Évaluation du projet pilote « Construis ton vélo ! ¼ par et pour les jeunes en milieu défavorisé : une intervention en contexte scolaire pour promouvoir la mobilité active

The densification of urban centers has driven individuals with low income toward more affordable suburban neighborhoods, thereby constraining transportation options due to car-centric planning and the difficulty for public transit systems to meet mobility needs. Recognizing that active cycling promotes travel autonomy, social participation, and physical and mental well-being, the promotion of such behavior through localized interventions stands as a critical objective to foster transport equity. In this context, in collaboration with the organization "Cyclo Nord-Sud," this study aims to explore the outcomes and favorable components of the "Build Your Bike!" pilot project offered as an extracurricular activity to high school students in a disadvantaged neighborhood. A qualitative, comprehensive approach with an inductive and phenomenological perspective was employed. We conducted a focus group at the end of the program and used conceptual categories to complete the analysis. The results revealed positive outcomes from the program related to: 1) well-being, 2) learning, 3) access to a bicycle, and 4) mobility. Favorable mechanisms encompassed: 1) the approach of adult mentors, 2) extracurricular involvement, 3) teamwork, 4) manual labor, and 5) bicycle ownership upon program completion. The mechanisms identified by the participants hold potential for improvement in future program iterations and can guide the development of similar interventions.

La densification des centres urbains a poussé les personnes à faible revenu vers des quartiers suburbains plus abordables, limitant les options en transport en raison de l'aménagement centré sur la voiture et de la difficulté pour le réseau de transports en commun de répondre aux besoins de mobilité. Étant donné que les déplacements actifs à vélo favorisent l'autonomie des déplacements, la participation sociale et sont source de bienfaits pour la santé physique et mentale, leur promotion par des interventions à l'échelle locale est un objectif essentiel pour favoriser l'équité en matière de transport. C'est dans ce cadre que, en collaboration avec l'organisme Cyclo Nord-Sud, cette étude vise à explorer les retombées et les composantes favorables du projet pilote « Construis ton vélo ! ¼ offert en parascolaire à des élèves du secondaire en milieu défavorisé. Une méthode qualitative de type compréhensive avec une approche inductive et phénoménologique a été utilisée. Elle a été complétée par un entretien de groupe à la fin du programme et une analyse par catégories conceptualisantes. Les résultats ont révélé que les retombées positives du programme se rapportent : 1) au bien-être ; 2) aux apprentissages ; 3) à l'accès à un vélo ; et 4) à la motilité. Les fonctionnements favorables sont : 1) l'approche des adultes encadrants, 2) le parascolaire, 3) le travail d'équipe, 4) le travail manuel et 5) le fait de posséder un vélo à la fin du programme. Les mécanismes identifiés par les jeunes pourront être valorisés dans les prochaines versions du programme et guider la création d'interventions similaires.

Physiological assessment of a 16 day, 4385 km ultra-endurance mountain bike race: A case study.

The Tour Divide (TD) is a 4385 km ultra-endurance bicycle race that follows the continental divide from Canada to Mexico. In this case study, we performed a comprehensive molecular and physiological profile before and after the completion of the TD. Assessments were performed 35 days before the start (Pre-TD) and ∼36 h after the finish (Post-TD). Total energy expenditure was assessed during the first 9 days by doubly labelled water (2 H2 18 O), abdominal and leg tissue volumes via MRI, and graded exercise tests to quantify fitness and substrate preference. Vastus lateralis muscle biopsies were taken to measure mitochondrial function via respirometry, and vascular function was assessed using Doppler ultrasound. The 47-year-old male subject took 16 days 7 h 45 min to complete the route. He rode an average of 16.8 h/day. Neither maximal O2 uptake nor maximal power output changed pre- to post-TD. Measurement of total energy expenditure and dietary recall records suggested maintenance of energy balance, which was supported by the lack of change in body weight. The subject lost both appendicular and trunk fat mass and gained leg lean mass pre- to post-TD. Skeletal muscle mitochondrial and vascular endothelial function decreased pre- to post-TD. Overall, exercise performance was maintained despite reductions in muscle mitochondrial and vascular endothelial function post-TD, suggesting a metabolic reserve in our highly trained athlete.

Conventional or parking-protected bike lanes? A Full-Bayesian before-and-after assessment.

OBJECTIVE: Biking infrastructure plays a crucial role in ensuring cyclists' safety and encouraging more people to bike. Recently, many North American municipalities started to adopt a new bike lane design, namely the parking-protected bike lane (PPBL), in which the bike lane is placed between the sidewalk and the parking lane. This study aims to assess the safety impacts associated with converting conventional bike lanes (CBLs) to PPBLs. METHODS: To that end, collision and traffic data were collected at 19 street sections from three corridors in Vancouver and Ottawa before and after the conversion. Poisson-Lognormal Linear Intervention model was developed to undertake a Full Bayesian before-and-after analysis to evaluate the change in the frequency of bike-vehicle collisions and other collaterally affected collisions (i.e., total and rear-end collisions) after implementing PPBLs. RESULTS: Reductions of 31.2%, 16.5%, and 4.4% were observed for total, rear-end, and bike collisions, respectively, after implementing the PPBLs, but the results varied significantly depending on the corridor characteristics. CONCLUSION: Overall, PPBLs demonstrated positive impacts on cyclist safety in some corridors, but their performance is highly sensitive to bike path opening density, intersection density, and intersection treatments.

Safety assessment of on-road cycling lanes: A comparative study of different layouts using driving simulator.

Over the past few decades, a growing attention has been directed toward cycling due to its positive impacts on social, economic, and health aspects. Various countries are adopting and implementing strategies to promote cycling as a daily mode of transport. The main objective of this study is to improve cyclists' safety by investigating the impact of different layouts of on-road cycle lanes at two-lane two-way roads on drivers' interactions with cyclists using driving simulator. Three layouts of on-road cycle lanes were tested and compared, namely, uncolored, colored, and island separation, along with a control case where no cycle lane was provided. In addition, the impact of road alignments (straight sections, left and right curves) and the presence of an opposing vehicle were investigated. The driving simulator at Qatar University was used to conduct this study. A total of 92 subjects participated in this study. According to the results, on-road cycle lanes can significantly increase the safety of cyclists compared to shared lanes with motorized traffic. Moreover, the results showed that the drivers' intrusion to the opposite lane in the presence of opposing vehicles can be eliminated by providing on-road cycle lanes. That is, drivers' crash risk can also be reduced through the provision of on-road cycle lanes. Comparison of different on-road cycle lane treatments showed that uncolored cycle lanes outperformed the other layouts in terms of lateral clearance between the driver and the cyclist for right and straight alignments. On the other hand, the colored cycle lane showed better results for the left alignment. The findings of this study could be useful for designing on-road bicycle infrastructure to eliminate possible vehicle-cyclist and vehicle-vehicle conflicts and minimize crash risk.

Risk Factors and Inequities in Transportation Injury and Mortality in the Canadian Census Health and Environment Cohorts (CanCHECs).

BACKGROUND: Road traffic injury contributes substantially to morbidity and mortality. Canada stands out among developed countries in not conducting a national household travel survey, leading to a dearth of national transportation mode data and risk calculations that have appropriate denominators. Since traffic injuries are specific to the mode of travel used, these risk calculations should consider travel mode. METHODS: Census data on mode of commute is one of the few sources of these data for persons aged 15 and over. This study leveraged a national data linkage cohort, the Canadian Census Health and Environment Cohorts, that connects census sociodemographic and commute mode data with records of deaths and hospitalizations, enabling assessment of road traffic injury associations by indicators of mode of travel (commuter mode). We examined longitudinal (1996-2019) bicyclist, pedestrian, and motor vehicle occupant injury and fatality risk in the Canadian Census Health and Environment Cohorts by commuter mode and sociodemographic characteristics using Cox proportional hazards models within the working adult population. RESULTS: We estimated positive associations between commute mode and same mode injury and fatality, particularly for bicycle commuters (hazard ratios for bicycling injury was 9.1 and for bicycling fatality was 11). Low-income populations and Indigenous people had increased injury risk across all modes. CONCLUSIONS: This study shows inequities in transportation injury risk in Canada and underscores the importance of adjusting for mode of travel when examining differences between population groups.

Development of the health economic assessment tool (HEAT) for walking and cycling: seventh consensus meeting: meeting report: 8 March and 5 April 2023

The project on the Health Economic Assessment Tool (HEAT) for Walking and Cycling,1 coordinated by WHO, steered by a coordinating team of multidisciplinary experts and supported by relevant international experts invited ad hoc, hold advisory group and consensus meetings to discuss and agree upon methodological updates and new features of the HEAT. The seventh meeting was convened to achieve scientific consensus on a new functionality for assessing the effects of e-biking. Twenty participants attended the meeting, comprising members of the HEAT coordinating team, the HEAT advisory group and invited experts, seven participants from WHO regions (five from the European Region and two from the Region of the Americas), and two from WHO headquarters. Participants discussed and adopted eight recommendations and provided comments, which will be taken into account in finalizing an updated version of the HEAT that includes e-biking.

Computer vision-based assessment of cyclist-tram track interactions for predictive modeling of crossing success.

INTRODUCTION: Single Bicycle Brashes (SBCs) are common, and underreported in official statistics. In urban environments, light rail tram tracks are a frequent factor, however, they have not yet been the subject of engineering analysis. METHOD: This study employs video-based analysis at nine Dublin city centre locations and introduces a predictive model for crossing success on tram tracks, utilising cyclist crossing angles within a Surrogate Measure of Safety (SMoS) framework. Additionally, Convolutional Neural Networks (CNNs) were explored for automatic estimation of crossing angles. RESULTS: Modelling results indicate that cyclist crossing angle is a strong predictor of crossing success, and that cyclist velocity is not. Findings also highlight the prevalence of external factors which limit crossing angles for cyclists. In particular, kerbs are a common factor, along with passing/approaching vehicles or other cyclists. Furthermore, results indicate that further training on a relatively small sample of 100 domain-specific examples can achieve substantial accuracy improvements for cyclist detection (from 0.31AP0.5 to 0.98AP0.5) and crossing angle inference from traffic camera footage. CONCLUSIONS: Ensuring safe crossing angles is important for cyclist safety around tram tracks. Infrastructural planners should aim for intuitive, self-explainable road layouts that allow for and encourage crossing angles of 60° or more - ideally 90°. PRACTICAL APPLICATIONS: The SMoS framework and the open-source SafeCross1 application offer actionable insights and tools for enhancing cyclist safety around tram tracks.

Integrating Equity Into Bicycle Infrastructure, Planning, and Programming: A Mixed Methods Exploration of Implementation Among Participants in the Bicycle Friendly Community Program.

INTRODUCTION: Integrating equity considerations into bicycle infrastructure, planning, and programming is essential to increase bicycling and reduce physical inactivity-related health disparities. However, little is known about communities' experiences with activities that promote equity considerations in bicycle infrastructure, planning, and programming or about barriers and facilitators to such considerations. The objective of this project was to gain in-depth understanding of the experiences, barriers, and facilitators that communities encounter with integrating equity considerations into bicycle infrastructure, planning, and programming. METHODS: We administered a web-based survey in 2022 to assess communities' experiences with 31 equity-focused activities in 3 areas: 1) community engagement, education, events, and programming (community engagement); 2) data collection, evaluation, and goal setting (data); and 3) infrastructure, facilities, and physical amenities (infrastructure). Respondents were people who represented communities in the US that participated in the League of American Bicyclists' Bicycle Friendly Community (BFC) Program. We then conducted 6 focus groups with a subset of survey respondents to explore barriers and facilitators to implementing equity-focused activities. RESULTS: Survey respondents (N = 194) had experience with a mean (SD) of 5.9 (5.7) equity-focused activities. Focus group participants (N = 30) identified themes related to community engagement (outreach to and engagement of underrepresented communities, cultural perceptions of bicycling, and funding and support for community rides and programs); data (locally relevant data); and infrastructure (political will, community design, and infrastructure). They described barriers and facilitators for each. CONCLUSION: Communities are challenged with integrating equity into bicycle infrastructure, planning, and programming. Multicomponent strategies with support from entities such as the BFC program will be required to make progress.

Changes in active commuting and changes in health: Within- and between-individual analyses among 16 881 Finnish public sector employees.

BACKGROUND: Active commuting, such as walking or cycling to work, can be beneficial for health. However, because within-individual studies on the association between change in active commuting and change in health are scarce, the previous results may have been biased due to unmeasured confounding. Additionally, prior studies have often lacked information about commuting distance. METHODS: We used two waves (2020, T1 and 2022, T2) of self-report data from the Finnish Public Sector study (N = 16,881; 80% female) to examine the within- and between associations (in a hybrid model) between active commuting and health. Exposure was measured by actively commuted kilometers per week, that is, by multiplying the number of walking or cycling days per week with the daily commuting distance. The primary outcome, self-rated health, was measured at T1 and T2. The secondary outcomes, psychological distress, and sleep problems were measured only at T2 and were therefore analyzed only in a between-individual design. RESULTS: After adjustment for potential time-varying confounders such as socioeconomic factors, body mass index, and health behaviors, an increase equivalent to 10 additional active commuting kilometers per week was associated with a small improvement in self-rated health (within-individual unstandardized beta = 0.01, 95% CI 0.01-0.02; between-individual unstandardized beta = 0.03, 95% CI 0.02-0.04). No associations were observed between changes in active commuting and psychological distress or sleep problems. CONCLUSIONS: An increase in active commuting may promote self-rated health. However, increase of tens of additional kilometers in commuting every day may be required to produce even a small effect on health.

Simulating the impact of particulate matter exposure on health-related behaviour: A comparative study of stochastic modelling and personal monitoring data.

Epidemiological and exposure studies concerning particulate matter (PM) often rely on data from sparse governmental stations. While low-cost personal monitors have some drawbacks, recent developments have shown that they can provide fairly accurate and fit-for-purpose data. Comparing a stochastic, i.e., agent-based model (ABM), with environmental, biometric and activity data, collected with personal monitors, could provide insight into how the two approaches assess PM exposure and dose. An ABM was constructed, simulating a PM exposure/dose assessment of 100 agents. Their actions were governed by inherent probabilities of performing an activity, based on population data. Each activity was associated with an intensity level, and a PM pollution level. The ABM results were compared with real-world results. Both approaches had comparable results, showing similar trends and a mean dose. Discrepancies were seen in the activities with the highest mean dose values. A stochastic model, based on population data, does not capture well some specifics of a local population. Combined, personal sensors could provide input for calibration, and an ABM approach can help offset a low number of participants. Implementing a function of agents influencing others transport choice, increased the importance of cycling/walking in the overall dose estimate. Activists, agents with an increased transport influence, did not play an important role at low PM levels. As concentrations rose, higher shares of activists (and their influence) caused the dose to increase. Simulating a person's PM exposure/dose in different scenarios and activities in a virtual environment provides researchers and policymakers with a valuable tool.

Assessment of child safety on bicycles in baby carriers - The importance of evaluating both head and neck injuries.

INTRODUCTION: The paper addresses an important accident type that involves children in bicycle seats - the bicycle fall over. It is a significant and common accident type and many parents have been reported to experience this type of "close call." The fall over occurs at low velocities and even while a bicycle is standing still, and may result from a split-second lack of attention on behalf of the accompanying adult (e.g. while loading groceries, i.e. while not being exposed to traffic per se). Moreover, irrespective of the low velocities involved, the trauma that may result to the head of the child is considerable and may be life-threatening, as shown in the study. METHOD: The paper presents two methods to address this accident scenario in a quantitative way: in-situ accelerometer-based measurement and numerical modeling approaches. It is shown that the methods produce consistent results under the prerequisites of the study. They are therefore promising methods to be used in the study of this type of accident. RESULTS: The importanance of the protective role of a child helmet is without discussion in everyday traffic.However, this study draws attention to one particular effect observed in this accident type: that the geometry of the helmet may at times expose the child's head to considerably larger forces, by having contact with the ground. The study also highlights the importance of neck bending injuries during bicycle fall over, which are often neglected in the safety assessment - not only for children in bicycle seats. The study concludes that considering only head acceleration may lead to biased conclusions about using helmets as protective devices.

How much behaviour change is required for the investment in cycling infrastructure to be sustainable? A break-even analysis.

BACKGROUND: Active travel has gained traction among policy makers as a promising solution to physical inactivity. Returns on active travel investments, including cycling infrastructure, crucially rely on resulting improvements in population behaviours. Estimating the expected economic value that an additional regular cyclist will generate and being able to identify the behaviour change required at the population level to offset the intervention costs is important to inform future investment decisions. METHODS: The WHO's Health Economic Assessment Tool was employed to conduct a break-even analysis. A case study methodology was used which focused on a real-world construction project of a separated cycleway in the UK. The economic assessment considered physical activity benefits, air pollution, crash risk and carbon emissions in monetary terms. An iterative computational approach was applied to identify the behaviour change (cycling) requirements, and corresponding benefits valued using international dollars, to break even on the investment costs. Sensitivity analyses were conducted to assess robustness of the base-case results. RESULTS: Over a ten-year time horizon, an additional regular cyclist (i.e., someone cycling most days of the week) was found to generate $798 (£533) per annum (international dollars). An additional 267 regular cyclists per km were required to break even on the construction of the new separated cycleway. Estimates were particularly sensitive to variations to age, cycling volume and evaluation time horizon. CONCLUSIONS: Policymakers planning to invest in cycling infrastructure should consider using these reproducible, order-of-magnitude estimates to complement the more comprehensive transport appraisal and budget allocation processes. This would ensure that, when considering its health-related economic benefits, the investment is justifiable on economic sustainability grounds.

Total Energy Expenditure and ad Libitum Fluid/Nutrient Intake During a 24-Hour Mountain-Bike Event: A Case Study.

Previous studies have used the doubly labeled water method to evaluate the total energy expenditure (TEE) during Ironman, ultramarathon trail runs, and competitive road cycling. However, the technique has not been applied to a 24-hour cross-country mountain-bike event. PURPOSE: This case study aimed to measure the TEE, cycling metrics, and ad libitum nutrient/fluid intake during a 24-hour cross-country mountain-bike race. METHODS: A trained male cyclist (41 y, 74.1 kg, 172.4 cm) received an oral dose of doubly labeled water prior to the 24-hour event for the calculations of TEE and water turnover. Nude body weight and urine samples were collected prerace, during the race, and postrace. Total nutrient intake and total fluid intake in addition to cycling metrics (speed, power output, cadence, and heart rate) were continuously recorded during the event. RESULTS: The rider completed 383 km coupled with a vertical gain of 7737 m during the 24-hour event. Average speed, power, and heart rate were 16.3 (2) km·h-1, 122 (29) W, and 134 (18) beats·min-1, respectively. TEE and total nutrient intake were 41 and 23.5 MJ, respectively. Total carbohydrate intake was 1192 g with an average hourly intake of 58 (22) g·h-1. Total body weight was 75.3 and 72.3 kg prerace and postrace, respectively, with a measured ad libitum total fluid intake of 13.3 L and a water turnover of 17.2 L. CONCLUSIONS: These data provide novel insights for measures of TEE, total energy intake, and total fluid intake during an ultraendurance cross-country mountain-biking event and provide a foundation for future race/training needs.

A Review of Cyclist Head Injury, Impact Characteristics and the Implications for Helmet Assessment Methods.

Head injuries are common for cyclists involved in collisions. Such collision scenarios result in a range of injuries, with different head impact speeds, angles, locations, or surfaces. A clear understanding of these collision characteristics is vital to design high fidelity test methods for evaluating the performance of helmets. We review literature detailing real-world cyclist collision scenarios and report on these key characteristics. Our review shows that helmeted cyclists have a considerable reduction in skull fracture and focal brain pathologies compared to non-helmeted cyclists, as well as a reduction in all brain pathologies. The considerable reduction in focal head pathologies is likely to be due to helmet standards mandating thresholds of linear acceleration. The less considerable reduction in diffuse brain injuries is likely to be due to the lack of monitoring head rotation in test methods. We performed a novel meta-analysis of the location of 1809 head impacts from ten studies. Most studies showed that the side and front regions are frequently impacted, with one large, contemporary study highlighting a high proportion of occipital impacts. Helmets frequently had impact locations low down near the rim line. The face is not well protected by most conventional bicycle helmets. Several papers determine head impact speed and angle from in-depth reconstructions and computer simulations. They report head impact speeds from 5 to 16 m/s, with a concentration around 5 to 8 m/s and higher speeds when there was another vehicle involved in the collision. Reported angles range from 10° to 80° to the normal, and are concentrated around 30°-50°. Our review also shows that in nearly 80% of the cases, the head impact is reported to be against a flat surface. This review highlights current gaps in data, and calls for more research and data to better inform improvements in testing methods of standards and rating schemes and raise helmet safety.

A modelling framework for local thermal comfort assessment related to bicycle helmet use.

Thermal discomfort due to accumulated sweat increasing head skin wettedness may contribute to low wearing rates of bicycle helmets. Using curated data on human head sweating and helmet thermal properties, a modelling framework for the thermal comfort assessment of bicycle helmet use is proposed. Local sweat rates (LSR) at the head were predicted as the ratio to the gross sweat rate (GSR) of the whole body or by sudomotor sensitivity (SUD), the change in LSR per change in body core temperature (Δtre). Combining those local models with Δtre and GSR output from thermoregulation models, we simulated head sweating depending on the characteristics of the thermal environment, clothing, activity, and exposure duration. Local thermal comfort thresholds for head skin wettedness were derived in relation to thermal properties of bicycle helmets. The modelling framework was supplemented by regression equations predicting the wind-related reductions in thermal insulation and evaporative resistance of the headgear and boundary air layer, respectively. Comparing the predictions of local models coupled with different thermoregulation models to LSR measured at the frontal, lateral and medial head under bicycle helmet use revealed a large spread in LSR predictions predominantly determined by the local models and the considered head region. SUD tended to overestimate frontal LSR but performed better for lateral and medial head regions, whereas predictions by LSR/GSR ratios were lower and agreed better with measured frontal LSR. However, even for the best models root mean squared prediction errors exceeded experimental SD by 18-30%. From the high correlation (R > 0.9) of skin wettedness comfort thresholds with local sweating sensitivity reported for different body regions, we derived a threshold value of 0.37 for head skin wettedness. We illustrate the application of the modelling framework using a commuter-cycling scenario, and discuss its potential as well as the needs for further research.