Assessing the unintended health impacts of road transport policies and interventions: translating research evidence for use in policy and practice

Recording harms in randomized controlled trials of behavior change interventions: a scoping review and map of the evidence

OBJECTIVES

Randomized controlled trials evaluate diverse interventions. This can include medical interventions such as drugs or surgical procedures, or behavior change interventions (BCIs) that aim to change a habit, belief, or attitude to improve health, for example, healthy eating, psychological wellbeing. Harms are often recorded poorly or inconsistently within randomized controlled trials of BCIs. This scoping review aimed to collate and describe literature on categories, definitions, and mechanisms of harms from BCIs; methods of identifying plausible harms; and recommendations for recording harms.

STUDY DESIGN AND SETTING

A scoping review was conducted. Three databases (MEDLINE, PsycINFO, and CINAHL) were searched. Reference list checking and citation searching were performed. Articles were included if they discussed (1) interventions that aimed to modify behavior, (2) categories or mechanisms of harms, and (3) methods or recommendations for recording harms. All research designs were included. One reviewer reviewed titles, abstracts, and full texts; queries were checked with another reviewer. Data were extracted and synthesized descriptively by one reviewer and checked by another reviewer. A thematic map was constructed to summarize the review findings. Harms described from specific BCIs were identified, and examples were selected and summarized.

RESULTS

The review included 37 articles. Nineteen of 37 articles contributed to a thematic review. Three articles described categories of harms; categories of harm included physical, psychological, group and social interactions, cultural, equity, opportunity cost, environmental, and economic. Seven articles included mechanisms or underlying factors for harms including feelings of failure leading to shame or stigma, and group interventions enabling knowledge exchange on unhealthy behaviors. Twelve articles provided recommendations for recording harms, including taking a proportionate approach by focusing on the most plausible and important harms, collecting different perspectives on whether harms had occurred (eg, caregivers and family members), and using qualitative research methods to identify harms. One article described a three-step method to identify plausible harms from an intervention, and six articles supported aspects of the method. Eighteen of 37 articles contributed to a review which collated harms arising from specific interventions, for example, a peer support intervention in inflammatory bowel disease caused distressing conversations which might lead to anxiety and confrontation with a possible negative future.

CONCLUSION

BCIs can cause harm. This review identified categories and proposed mechanisms of harms, as well as methods and recommendations for identifying and recording harms in BCIs for inclusion in forthcoming recommendations.

Health Promotion Interventions on Helmet Use: A Systematic Review and Meta-Analysis of Pre-Test and Post-Test Studies

Background

We aimed to review the effectiveness of health promotion interventions in the use of helmet and to identify the types of effective health promotion strategies among the examined studies.

Methods

A systematic search was performed on the PubMed, Scopus, Cochrane, and Embase databases up to 1 Aug 2022 to find the studies evaluated the effectiveness of health promotion interventions for helmet use among target population. In this systematic review and meta-analysis, interventions with pre- post-test design were included. The dependent variable of the study is the percentage of participants who responded positively toward helmet use in the baseline and after the interventions. Random-effects models were used to pool study results.

Results

Overall, 1,675 articles were found in the initial search and entered into the Endnote software. Of these, 917 duplicate articles were removed, leaving 758 articles were screened based on title and abstract. Finally, 12 eligible articles were included in the review and five with pre and post-test design were included in the meta-analysis. The overall random-effects pooled estimation of persons wearing helmets before and after interventions was 70% (95%CI 21 -119; P<0.001), without a heterogeneity (I2 =0%; P=0.94), which means that the average percentage of changing to helmet use is 70%. Community-based education program was the most commonly applied for interventional studies. The next most commonly used approaches were campaign designing.

Conclusion

Wearing helmet approximately increased 70% among participant. Health promotion strategies may target helmet-wearing behavior to reduce head injuries in motorcyclist road traffic accidents.

Inclusion of Health in Environmental Impact Assessment of Major Transport Infrastructure Projects in Vietnam

Background: Infrastructure spending, especially in the transport sector, is expected to increase rapidly in Vietnam. This boost in transportation investment impacts health. Environmental impact assessments (EIAs) are essential tools for decision-making to reduce and mitigate anticipated impacts of development projects, and integration of health assessment as an essential part of the EIA process has been regulated in many high-income countries. There is, however, limited knowledge about how health is evaluated in these environmental assessments in low- and middle-income countries (LMICs) such as Vietnam.

Methods: We did an analysis of EIAs of four major transport projects in Vietnam, applying a six-step coding framework previously used to investigate EIAs in the Australian context.

Results: We found that health was inadequately considered in all four EIAs. There was no direct health assessment within the four EIAs due to the lack of formal requirements from either Government or the financing agency, the Asian Development Bank (ADB). Health issues were often identified as risks posed by the projects within the assessment of impacts on environmental conditions. A broader consideration of health was limited. When social outcomes of the projects were present in EIAs, they were often mentioned once without any detailed assessment or linking to health. There was no evidence linking health benefits and shifts towards active travel with the construction of two metro rail projects. Mitigation measures offered in all four EIAs were found to be generic and insubstantial.

Conclusion: The health assessments in the EIAs of four transport projects in Vietnam were significantly less detailed than those in Australia, mainly due to the lack of legislative requirements. The lack of health content indicates the need for involvement of health experts in the environmental assessment process, as well as requirements for the health assessment to be integrated in EIA. Our findings suggest there is the need to build capacity both within and outside of government to fully consider the health impacts of infrastructure in EIA practice.

A push for public health: the effect of e-bikes on physical activity levels

Background

Cycling is considered to have a positive effect on public health through increased physical activity. In Norway, the e-bike is seen as a way of getting more people to cycle. However, the motorized assistance of an e-bike potentially eliminates any physical activity associated with its use. It is possible that the assumed health effect of increased cycling is “erased” through a reduction in other physical activities (a substitution effect). In this paper we study the public health effects of e-bikes using a combined cross-sectional and quasi-experimental design. First, we explore the existence of potentially hedonistic values in relation to interest in acquiring an e-bike and, second, we conduct an intervention study of physical activity pre- and post-purchase.

Methods

A sample of 340 people responded to a questionnaire before buying an e-bike and follow-up 4 weeks later, when 45 had bought one. A further 28 (mainly physically inactive) were recruited through a Norwegian NGO. For a comparison group, 1995 people were recruited through the Falck National Register of Bicycle Owners. All respondents were asked about the intensity of their cycling, (kilometres cycled in the previous week), walking and physical activity in addition to cycling as means of transport (days and hours).

Results

A structural equation model showed that hedonistic life values, and general physical activity, were predictive of interest in buying an e-bike. However people who already cycled a lot showed less interest. The trial showed that increased cycling – whether as a mean of transport or exercise –was related to higher levels of total physical activity in both groups compared to a comparison group (one-way ANOVA).

Conclusions

Our findings indicate that in the Norwegian cycle population there is no substantial substitution effect of physical activity with the introduction of an e-bike. The appeal of the e-bike is strongest among those with little existing interest in, or levels of, physical activity. The net effect of the e-bike therefore seems positive from a public health perspective.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4817-3) contains supplementary material, which is available to authorized users.

Effects of new urban motorway infrastructure on road traffic accidents in the local area: a retrospective longitudinal study in Scotland

BACKGROUND

The M74 motorway extension, Glasgow, opened in June 2011. One justification for construction was an expectation that it would reduce road traffic accidents (RTAs) on local non-motorway roads. This study evaluated the impact of the extension on the number of RTAs, stratifying by accident severity.

METHODS

Data for the period 1997-2014 were extracted from a UK database of reported RTAs involving a personal injury. RTA severity was defined by the level of injury: minor, severe or fatal. RTAs were assigned to (1) the local area surrounding the motorway extension, (2) a comparator area surrounding an existing motorway or (3) a control area elsewhere in the conurbation. Interrupted time-series regression with autoregressive integrated moving average (ARIMA) errors was used to determine longitudinal between-area differences in change in the number of RTAs, which might indicate an intervention effect.

RESULTS

Glasgow and surrounding local authorities saw a 50.6% reduction in annual RTAs (n: 5901 to 2914) between 1997 and 2014. In the intervention area, the number of recorded RTAs decreased by 50.7% (n: 758 to 374), and that of fatal/severe RTAs by 57.4% (n: 129 to 55), with similar reductions in the comparator/control areas. The interrupted time-series analysis showed no significant between-area differences in temporal trends. The reduction of pedestrian casualties was attenuated in the intervention area relative to Glasgow and surrounding authorities.

CONCLUSIONS

Reduction in RTAs was not associated with the motorway extension. Our findings suggest that in planning future investment, it should not be taken for granted that new road infrastructure alone will reduce RTAs in local areas. Urbanisation is proceeding rapidly worldwide, and evidence of infrastructure changes is lacking; this novel study provides important findings for future developments.

Health impact assessment of transport policies in Rotterdam: Decrease of total traffic and increase of electric car use

BACKGROUND

Green house gas (GHG) mitigation policies can be evaluated by showing their co-benefits to health.

METHOD

Health Impact Assessment (HIA) was used to quantify co-benefits of GHG mitigation policies in Rotterdam. The effects of two separate interventions (10% reduction of private vehicle kilometers and a share of 50% electric-powered private vehicle kilometers) on particulate matter (PM2.5), elemental carbon (EC) and noise (engine noise and tyre noise) were assessed using Years of Life Lost (YLL) and Years Lived with Disability (YLD). The baseline was 2010 and the end of the assessment 2020.

RESULTS

The intervention aimed at reducing traffic is associated with a decreased exposure to noise resulting in a reduction of 21 (confidence interval (CI): 11-129) YLDs due to annoyance and 35 (CI: 20-51) YLDs due to sleep disturbance for the population per year. The effects of 50% electric-powered car use are slightly higher with a reduction of 26 (CI: 13-116) and 41 (CI: 24-60) YLDs, respectively. The two interventions have marginal effects on air pollution, because already implemented traffic policies will reduce PM2.5 and EC by around 40% and 60% respectively, from 2010 to 2020.

DISCUSSION

The evaluation of planned interventions, related to climate change policies, targeting only the transport sector can result in small co-benefits for health, if the analysis is limited to air pollution and noise. This urges to expand the analysis by including other impacts, e.g. physical activity and well-being, as a necessary step to better understanding consequences of interventions and carefully orienting resources useful to build knowledge to improve public health.

The German Energiewende-a matter for health?

BACKGROUND

Germany's enormous transformation away from nuclear energy and fossil fuels towards a renewable and energy efficient system-called the Energiewende-is playing an essential role in Germany's economy and policymaking. This article summarises the current knowledge on possible health impacts of the Energiewende and describes the need and opportunities to incorporate health into energy-related policy.

METHODS

A structural model helped to narrow down specific topics and to conceptualise links between the Energiewende, the environment and health. A comprehensive literature search was conducted within policy documents and scientific databases with English and German language selections.

RESULTS

Of 7800 publications first identified only 46 explicitly related energy measures to health, of which 40 were grey literature. Notably, only 12% published by health authorities all others were issued by environmental, energy or consumer protection agencies, ministries or institutions.

CONCLUSION

Our study shows that health impacts of the German Energiewende are rarely explicitly addressed. An integration of a health perspective into energy-related policy is needed including the involvement of public health authorities. A health impact assessment can be a suitable tool to support and evaluate Energiewende-related developments from a health perspective.

Rapid Assessment of Environmental Health Impacts for Policy Support: The Example of Road Transport in New Zealand

An integrated environmental health impact assessment of road transport in New Zealand was carried out, using a rapid assessment. The disease and injury burden was assessed from traffic-related accidents, air pollution, noise and physical (in)activity, and impacts attributed back to modal source. In total, road transport was found to be responsible for 650 deaths in 2012 (2.1% of annual mortality): 308 from traffic accidents, 283 as a result of air pollution, and 59 from noise. Together with morbidity, these represent a total burden of disease of 26,610 disability-adjusted life years (DALYs). An estimated 40 deaths and 1874 DALYs were avoided through active transport. Cars are responsible for about 52% of attributable deaths, but heavy goods vehicles (6% of vehicle kilometres travelled, vkt) accounted for 21% of deaths. Motorcycles (1 per cent of vkt) are implicated in nearly 8% of deaths. Overall, impacts of traffic-related air pollution and noise are low compared to other developed countries, but road accident rates are high. Results highlight the need for policies targeted at road accidents, and especially at heavy goods vehicles and motorcycles, along with more general action to reduce the reliance on private road transport. The study also provides a framework for national indicator development.

Burden of disease caused by local transport in Warsaw, Poland

Transport is a major source of air pollution, noise, injuries and physical activity in the urban environment. The quantification of the health risks and benefits arising from these factors would provide useful information for the planning of cost-effective mitigation actions. In this study we quantified the burden of disease caused by local transport in the city of Warsaw, Poland. The disability-adjusted life-years (DALYs) were estimated for transport related air pollution (particulate matter (PM), nitrogen oxides (NO _x ), sulfur dioxide (SO₂), benzo[a]pyrene (BaP), cadmium, lead and nickel), noise, injuries and physical activity. Exposure to these factors was based on local and international data, and the exposure-response functions (ERFs) were based on published reviews and recommendations. The uncertainties were quantified and propagated with the Monte Carlo method. Local transport generated air pollution, noise and injuries were estimated to cause approximately 58,000 DALYs in the study area. From this burden 44% was due to air pollution and 46% due to noise. Transport related physical activity was estimated to cause a health benefit of 17,000 DALYs. Main quantified uncertainties were related to disability weight for the annoyance (due to noise) and to the ERFs for fine particulate matter (PM_2.5) air pollution and walking. The results indicate that the health burden of transport could be mitigated by reducing motorized transport, which causes air pollution and noise, and by encouraging walking and cycling in the study area.

Health impact assessment of active transportation: A systematic review

OBJECTIVE

Walking and cycling for transportation (i.e. active transportation, AT), provide substantial health benefits from increased physical activity (PA). However, risks of injury from exposure to motorized traffic and their emissions (i.e. air pollution) exist. The objective was to systematically review studies conducting health impact assessment (HIA) of a mode shift to AT on grounds of associated health benefits and risks.

METHODS

Systematic database searches of MEDLINE, Web of Science and Transportation Research International Documentation were performed by two independent researchers, augmented by bibliographic review, internet searches and expert consultation to identify peer-reviewed studies from inception to December 2014.

RESULTS

Thirty studies were included, originating predominantly from Europe, but also the United States, Australia and New Zealand. They compromised of mostly HIA approaches of comparative risk assessment and cost-benefit analysis. Estimated health benefit-risk or benefit-cost ratios of a mode shift to AT ranged between -2 and 360 (median=9). Effects of increased PA contributed the most to estimated health benefits, which strongly outweighed detrimental effects of traffic incidents and air pollution exposure on health.

CONCLUSION

Despite different HIA methodologies being applied with distinctive assumptions on key parameters, AT can provide substantial net health benefits, irrespective of geographical context.

Characteristics of health impact assessments reported in Australia and New Zealand 2005-2009

Abstract

Objective

: To describe the use and reporting of Health Impact Assessment (HIA) in Australia and New Zealand between 2005 and 2009.

Methods

: We identified 115 HIAs undertaken in Australia and New Zealand between 2005 and 2009. We reviewed 55 HIAs meeting the study's inclusion criteria to identify characteristics and appraise the quality of the reports.

Results

: Of the 55 HIAs, 31 were undertaken in Australia and 24 in New Zealand. The HIAs were undertaken on plans (31), projects (12), programs (6) and policies (6). Compared to Australia, a higher proportion of New Zealand HIAs were on policies and plans and were rapid assessments done voluntarily to support decision-making. In both countries, most HIAs were on land use planning proposals. Overall, 65% of HIA reports were judged to be adequate.

Conclusion

: This study is the first attempt to empirically investigate the nature of the broad range of HIAs done in Australia and New Zealand and has highlighted the emergence of HIA as a growing area of public health practice. It identifies areas where current practice could be improved and provides a baseline against which future HIA developments can be assessed.

Implications:

There is evidence that HIA is becoming a part of public health practice in Australia and New Zealand across a wide range of policies, plans and projects. The assessment of quality of reports allows the development of practical suggestions on ways current practice may be improved. The growth of HIA will depend on ongoing organisation and workforce development in both countries.

A scoping review of unintended harm associated with public health interventions: towards a typology and an understanding of underlying factors

OBJECTIVES

Unintended harm theory as related to public health interventions (PHI) is under developed, with harm evaluation and reporting often absent or incomplete. This review presents a typology for, and underlying factors linked to, PHI-associated unintended harm.

METHODS

This scoping review was conducted electronically and includes articles from 1992 to June of 2013. Out of 2,490 originally identified titles, 26 full-text articles were included that discussed unintended harm associated with PHI. An iterative data analysis process was utilized to identify both a typology and underlying factors associated with unintended harm.

RESULTS

A typology of PHI-associated unintended harm was identified: (1) physical; (2) psychosocial; (3) economic; (4) cultural and (5) environmental. Five underlying factors associated with PHI unintended harm emerged: (1) limited and/or poor quality evidence; (2) prevention of one extreme leads to another (boomerang effects); (3) lack of community engagement; (4) ignoring root causes; and (5) higher-income country PHI implementation in a lower- or middle-income country.

CONCLUSIONS

PHI planning and evaluation frameworks may benefit from the consideration and potential incorporation of the unintended harm typology and underlying factors.

Reducing cardiovascular health impacts from traffic-related noise and air pollution: intervention strategies

Recent studies suggest that exposure to both traffic-related air pollution (TrAP) and to road traffic noise (RTN) are independent risk factors for cardiovascular disease (CVD). While the exact pathophysiologic mechanisms are not known, plausible biological models exist for both associations. This paper describes interventions and mitigating measures aimed at reducing both air and noise pollution emitted from traffic. Nine types of interventions are examined within the four strategic themes of (i) land-use planning and transportation management, (ii) reduction of vehicle emissions, (iii) modification of existing structures, and (iv) behavioral change. Not all interventions result in concomitant reductions of air and noise pollutant exposures. Most interventions that rely on a scientific basis to reduce CVD are directed at reducing TrAP. Interventions identified with the greatest potential benefits focus on the pollutant source, such as reductions in traffic volume and air pollutant emissions, and are more easily realized, and likely cheaper, if they are considered in the land-use planning stages with less reliance on behavioral changes.

The potential modal shift and health benefits of implementing a public bicycle share program in Montreal, Canada

BACKGROUND

This study estimated the modal shift associated with the implementation of a public bicycle share program in Montreal, Canada.

METHODS

A population-based sample of adults participated in two cross sectional telephone surveys. Self-reported travel behaviors were collected at the end of the first (fall 2009) and second (fall 2010) season of implementation. The sample included 2502 (Mean age=47.8 years, 61.8% female), and 2509 (Mean age=48.9 years, 59.0% female) adult respondents in each survey.

RESULTS

The estimated modal shift associated with the implementation of the PBSP from motor vehicle use to walking, cycling, and public transportation was 6483 and 8023 trips in 2009 and 2010. This change represents 0.34% and 0.43% of all motor vehicle trips in Montreal.

CONCLUSIONS

The implementation of a PBSP was associated with a shift toward active transportation. The modal shift was complex and not simply the result of a discrete shift from one mode to another. Promotion of active transportation should encourage integration of multiple active transportation modes to better reflect people's actual transportation behaviors.

Integrated health impact assessment of travel behaviour: model exploration and application to a fuel price increase

Transportation policy measures often aim to change travel behaviour towards more efficient transport. While these policy measures do not necessarily target health, these could have an indirect health effect. We evaluate the health impact of a policy resulting in an increase of car fuel prices by 20% on active travel, outdoor air pollution and risk of road traffic injury. An integrated modelling chain is proposed to evaluate the health impact of this policy measure. An activity-based transport model estimated movements of people, providing whereabouts and travelled kilometres. An emission- and dispersion model provided air quality levels (elemental carbon) and a road safety model provided the number of fatal and non-fatal traffic victims. We used kilometres travelled while walking or cycling to estimate the time in active travel. Differences in health effects between the current and fuel price scenario were expressed in Disability Adjusted Life Years (DALY). A 20% fuel price increase leads to an overall gain of 1650 (1010-2330) DALY. Prevented deaths lead to a total of 1450 (890-2040) Years Life Gained (YLG), with better air quality accounting for 530 (180-880) YLG, fewer road traffic injuries for 750 (590-910) YLG and active travel for 170 (120-250) YLG. Concerning morbidity, mostly road safety led to 200 (120-290) fewer Years Lived with Disability (YLD), while air quality improvement only had a minor effect on cardiovascular hospital admissions. Air quality improvement and increased active travel mainly had an impact at older age, while traffic safety mainly affected younger and middle-aged people. This modelling approach illustrates the feasibility of a comprehensive health impact assessment of changes in travel behaviour. Our results suggest that more is needed than a policy rising car fuel prices by 20% to achieve substantial health gains. While the activity-based model gives an answer on what the effect of a proposed policy is, the focus on health may make policy integration more tangible. The model can therefore add to identifying win-win situations for both transport and health.

Community severance and health: what do we actually know?

Community severance occurs where road traffic (speed or volume) inhibits access to goods, services, or people. Appleyard and Lintell's seminal study of residents of three urban streets in San Francisco found an inverse relationship between traffic and social contacts. The extent of social networks predicts unhealthy behaviors, poor health, and mortality; high rather than low social integration is associated with reduced mortality, with an effect size of similar magnitude to stopping smoking. Although community severance diminishes social contacts, the implications of community severance for morbidity and mortality have not been empirically established. Based on a systematic literature search, we discuss what is actually known about community severance. There is empirical evidence that traffic speed and volume reduces physical activity, social contacts, children's play, and access to goods and services. However, no studies have investigated mental or physical health outcomes in relation to community severance. While not designed specifically to do so, recent developments in road design may also ameliorate community severance.

[Moving forward in health impact assessment: analysis of the non-health public policies of the Basque Government (Spain) as step prior to systematic screening]

Health not only depends on biologic or lifestyle factors but also on other economic, social, political, and environmental factors that shape the way people live and become ill. Thus, health policies are not the only policies affecting health, and consequently governments are increasingly interested in identifying the effect of other non-health policies on health. Health impact assessment is a prospective methodology that aims to predict the health impacts of policies before their implementation so that modifications can be suggested to maximize positive effects and avoid unexpected negative repercussions on health. The first stage in this process is screening, which can be used to select the interventions that could benefit from complete health impact assessment. Since resources are limited and not all government interventions can be assessed, tools that allow prioritization are essential. As a first stage in the validation of a systematic screening tool for health impact assessment in Spain, this article presents the process of compiling and classifying the non-health public policies of the eighth term of office of the Basque Government. Of the 97 policies analyzed, 76% were related to structural determinants of health inequalities, 79% were tactical or operational, 67% were aimed at specific population groups, and 66% were already implemented. The technical staff of other participating departments perceived the entire process of this initiative and its rationale positively. This initial experience allowed the planning of non-health policies in the Basque Country to be determined in detail as a means to move forward in incorporating impact on health in all policies.

Our environment, our health: a community-based participatory environmental health survey in Richmond, California

This study presents a health survey conducted by a community-based participatory research partnership between academic researchers and community organizers to consider environmental health and environmental justice issues in four neighborhoods of Richmond, California, a low-income community of color living along the fence line of a major oil refinery and near other industrial and mobile sources of pollution. The Richmond health survey aimed to assess local concerns and perceptions of neighborhood conditions, health problems, mobile and stationary hazards, access to health care, and other issues affecting residents of Richmond. Although respondents thought their neighborhoods were good places to live, they expressed concerns about neighborhood stressors and particular sources of pollution, and identified elevated asthma rates for children and long-time Richmond residents. The Richmond health survey offers a holistic, community-centered perspective to understanding local environmental health issues, and can inform future environmental health research and organizing efforts for community-university collaboratives.

Are cars the new tobacco?

BACKGROUND

Public health must continually respond to new threats reflecting wider societal changes. Ecological public health recognizes the links between human health and global sustainability. We argue that these links are typified by the harms caused by dependence on private cars.

METHODS

We present routine data and literature on the health impacts of private car use; the activities of the 'car lobby' and factors underpinning car dependence. We compare these with experience of tobacco.

RESULTS

Private cars cause significant health harm. The impacts include physical inactivity, obesity, death and injury from crashes, cardio-respiratory disease from air pollution, noise, community severance and climate change. The car lobby resists measures that would restrict car use, using tactics similar to the tobacco industry. Decisions about location and design of neighbourhoods have created environments that reinforce and reflect car dependence. Car ownership and use has greatly increased in recent decades and there is little public support for measures that would reduce this.

CONCLUSIONS

Car dependence is a potent example of an issue that ecological public health should address. The public health community should advocate strongly for effective policies that reduce car use and increase active travel.

Do the health benefits of cycling outweigh the risks?

BACKGROUND

Although from a societal point of view a modal shift from car to bicycle may have beneficial health effects due to decreased air pollution emissions, decreased greenhouse gas emissions, and increased levels of physical activity, shifts in individual adverse health effects such as higher exposure to air pollution and risk of a traffic accident may prevail.

OBJECTIVE

We describe whether the health benefits from the increased physical activity of a modal shift for urban commutes outweigh the health risks.

DATA SOURCES AND EXTRACTION

We have summarized the literature for air pollution, traffic accidents, and physical activity using systematic reviews supplemented with recent key studies.

DATA SYNTHESIS

We quantified the impact on all-cause mortality when 500,000 people would make a transition from car to bicycle for short trips on a daily basis in the Netherlands. We have expressed mortality impacts in life-years gained or lost, using life table calculations. For individuals who shift from car to bicycle, we estimated that beneficial effects of increased physical activity are substantially larger (3-14 months gained) than the potential mortality effect of increased inhaled air pollution doses (0.8-40 days lost) and the increase in traffic accidents (5-9 days lost). Societal benefits are even larger because of a modest reduction in air pollution and greenhouse gas emissions and traffic accidents.

CONCLUSIONS

On average, the estimated health benefits of cycling were substantially larger than the risks relative to car driving for individuals shifting their mode of transport.