Mobility is a major source of carbon gas emissions around the world. In Switzerland, transportation uses up 38% of total energy consumption and is therefore responsible for emitting 14.8 million tons of CO2 (not including international air traffic), which is the equivalent of one third of nationwide greenhouse gas emissions.63 In addition to greenhouse gases, motorized vehicles emit various pollutants, such as nitrogen oxide (NOx), fine particles (PM10 and PM2.5), and various volatile organic composite materials, which contribute to ozone (O3) peaks. These pollutants increase the decay of natural environments and affect vegetable growth.64 Tire-rubbing and abrasion from brakes also produce particles and micro pollutants that contribute to polluting terrestrial and aquatic ecosystems. A study estimates that global road traffic pro-duces 100,000 tons of micro plastics per year due to tire wear and tear, 40,000 tons of micro plastics per year due to break wear and tear, and that around 30% of those pollutants are transported and accumulating in the oceans. 65 Prior to even going into use, the production of vehicles and the construction of road infrastructure requires non-renewable resources to be extracted, fragmenting natural spaces to the detriment of the plant and animal species that inhabit them, and also contributing to emitting atmospheric pollutants and greenhouse gases.66
Motorized mobility affects health in a variety of ways.67-69 Air pollution (e.g., NO2, PM2.5, PM10, O3), which heat engines contribute to, is responsible for cardiovascular and respiratory illnesses.70 A study by the Federal Office for Territorial Development (ARE) estimates that air pollution in Switzerland is behind 2,200 premature deaths per year.71 The European Environmental Agency estimates that there are closer to 4,500 premature air pollution-related deaths in Switzerland (PM2.5, NO2, O3).64 The noise is associated with developing cardiovascular diseases, and harmful effects on sleep, stress, and the cognitive development of children are an established fact.72,73 Using cars reinforces the population’s sedentari-ness (since time spent sitting in the car reduces the time they devote to physical activity), which is associated to a whole array of non-communicable diseases, such as type II diabetes, cardiovascular and respiratory illnesses, and several types of cancer.74,75 A systematic review also shines a light on the fact that car use is associated with obesity.76 Finally, cars are often involved in road accidents.
Furthermore, road traffic congestion, roads and parking places taking up public space, barrier effects related to those infrastructures, as well as the heat islands they promote, all contribute to the degradation of living environments, to the detriment of both green and meeting spaces, thereby weakening social capital.69
Replacing combustion engine vehicles with electric vehicles is an often-privileged solution to issues regarding mobility. While such vehicles do provide a solution to the issue of air pollution in urban areas, they do not provide any solutions for road accidents, sedentary lifestyles, the use of public space, the extraction of resources, including rare-earth metals, under often dubious environmental and social conditions, and only partially to the issue of noise, since tire-rubbing is one of the primary sources of noise pollution, particularly at higher speeds.77
The WHO recommends a minimum of 150 minutes of moderate physical activity for adults per week,78 but a growing number of people do not meet this goal. In Switzerland, the OFS estimated in 2012 that 28% of the population was insufficiently active or totally inactive. Lack of time is often put forth to explain the difficulty of committing to a regular physical activity.68,79,80
Active mobility refers to modes of transportation that use human energy as their primary source of energy, and thus is used primarily in relation to bicycles (mechanical or electronically assisted) and walking. By allowing commute times to be combined with physical activity, as for instance when one bikes to get to work, bike mobility can contribute to making physical activity a part of people’s daily routines, thereby making it notably beneficial in terms of public health. A survey of bicycle users in Switzerland shows that nearly all bike users are aware that their trips allow them to combine exercising and commuting, and thus to incorporate physical activity into their daily routines.81 Several studies have shown that regularly committing to some kind of active mobility (such as biking) is associated to reduction in cardiovascular illness.82,83 A prospective group study has shown that active mobility is associated with a reduction in cardiovascular diseases, cancer, and all causes of death.84 Users also mention the mental benefits that comes from biking regularly. Daily commutes can become pleasant moments, giving people some time to decompress, a positive sensory experience of their environment, and the pleasure of riding a bicycle.81,85 It should be noted that the health benefits also apply to using electronically assisted bicycles.86
The health benefits of increased physical activity are particularly pronounced for the least active individuals. If active mobility can be seen as safe and effective, these modes can allow the part of the population that is least inclined towards physical activity to be more active in their daily life.80
One perception that is holding back the ex-pansion of active mobility is that walking or pedaling through high-traffic areas increases exposure to and inhalation of atmospheric pollutants, as well as the risk of traffic accidents. Yet moving bike paths a few meters away from traffic-dense routes significantly reduces exposure to pollutants. Furthermore, studies assessing the impact on health show that the benefits that come with increasing one’s physical activity by being actively mobile very much outweigh the negative effects of being exposed to air pollution or traffic accidents.2,80,87,88 Kriit et al. estimate, for instance, that investing in bike infrastructure in Stockholm would result in an annual reduction in health costs of 12.5 million euros due to an increase in physical activity, in 1.2 million euros due to the reduced exposure to pollution for the overall population, with additional costs of 0.3 million euros due to the increased exposure of new cyclists to air pollution and of 2.0 million euros related to the higher risk of accidents.88
Finally, appropriate infrastructure as well as reaching critical mass can significantly reduce the risks of accidents, including by providing separations from car traffic, better visibility for cyclists and pedestrians, and by having car drivers pay closer attention.89,90 Thus, the risk per kilometer travelled for one individual on a bicycle diminishes when the number of kilometers travelled by bicycle by the regional population increases (this is the “safety in numbers” phenomenon).91 A modal shift away from cars and towards active modes of mobility, along with a reduction in the number of cars in urban areas, makes it possible to diminish air pollution and the risks of accidents, and to thus begin a virtuous circle that increases the appeal of active mobility and reduces the overall population’s exposure to pollution.
Encouraging activity mobility and reducing car use makes it possible to reduce both air and noise pollution, as well as traffic accidents, and to make cities more pleasant.68,72,87,92 More generally, mobility issues are closely linked to urban planning. Cars have a strong hold on public spaces. To move one person around, cars require considerably more room as compared to public transport or active modes of mobility. Heran estimates, for instance, that a car trip requires 50 to 300 times as much space, depending on which hypothesis one goes with, than a trip made using another means of transportation.69 In urban centers where space is limited, road infrastructure leaves little space for other modes of mobility, as well as for green and meeting spaces, which make it easier to regulate temperature, drain rainwater, engage in leisure activities, and strengthen social capital, thereby contributing to the population’s physical and mental well-being.2,85,92-94
Finally, active mobility costs local governance significantly less than other means of transportation. Heran reports gaps of 1 to 10, 30, or even 50 in terms of costs when it comes to planning layouts for pedestrians and bicycles versus road plans for cars that will be used for individual motorized vehicles as well as public transportation. 69 An ARE study estimates that the annual profit, in terms of health, that would result from more active mobility is worth 1.4 billion CHF in Switzerland, where-as private cars are estimated to incur a cost of CHF 7.6 billion.71 Nieuwenhuijsen and Khreis92 estimate that traffic jams, pollution, and road accidents cost EU member countries 502 billion euros per year. An economic and health evaluation estimated that investing in bikeable infrastructure in the city of Stockholm would generate a profit, given the health benefits related to an increase in its population’s physical activity.88 Several authors encourage taking into account the impact on health of various means of transportation when drawing up budgetary overviews of mobility policies.67,90,95,96 In order to encourage taking into account the impact on health of different means of transportation in budgetary overviews and mobility policy strategies, the WHO has developed a tool (the (Health Economic Assessment Tool (HEAT)97), which allows one to easily model the benefits of a modal shift towards walking or biking. A master’s thesis done at the University of Lausanne uses the HEAT tool to estimate that in Lausanne, increasing the modal portion of bike trips from 1.2% (the 2015 figure) to 5% from 2015 to 2025 would allow 34 premature deaths to be avoid-ed over the course of 10 years, and 160 million euros to be saved over the course of 10 years.98
Active mobility does not, of course, offer a single solution to all of mobility issues. Distance, topography, and physical condition all deter-mine the possibility of modal shifts towards active mobility. Recommending a modal shift to public transportation, or a combination of active mobility and public transportation, is sometimes more appropriate. It may sometimes even be most appropriate to question the trip itself. And yet, in Switzerland, over 60% of trips involve less than 5km of travelling. That distance is typically considered accessible on a mechanical bicycle. It is estimated that electronically assisted bikes render trips of up to 10-15 km accessible (80% of trips are under 15km in length).89 Active mobility therefore has a lot of potential, both in urbans centers and in urban conglomerations when electronically assisted bicycles are used.
If there are both environmental and health-based arguments for promoting active mobility, then how can such a modal shift be encouraged? Understanding how accessible these modes are means taking into account the built environment (I.e., the existence and quality of bikeable and walkable infrastructure), transportation policies, and social norms regarding different modes of transportation. It is, for instance, an established fact that safe, continuous bikeable infrastructures make it possible for a wider array of people to use them, particularly as far as gender, age brackets, abilities, and motivation go. In areas where there is sufficient infrastructure (e.g., Copenhagen, Amsterdam), choosing to use a bike is seen as a logical choice for ease, speed, and financial reasons. A study by Rérat et al.89 concludes that the bikeable infrastructure in Switzerland is largely insufficient to promote real widespread use of bicycles for daily transportation needs. The authors point out that there are four groups of cyclists described in the literature.99 Those who are comfortable biking even in the absence of any infrastructure (<1%), motivated, confident cyclists who require a minimum amount of infrastructure (6%), those who would be in-terested in traveling by bike if the infrastructure were well-developed enough to ensure their security (60%), and those who have no intention of using a bicycle to get around (33%). These estimates reveal the vast potential reserve of cyclists from the third group. Recognizing the potential, in terms of public health, of promoting active mobility, such as biking, should encourage investing in bikeable infrastructure, legitimize active mobility as a means of transportation, and thereby make it accessible to many people. The role of health professionals as advocates is potentially crucial and could encourage and accelerate public policy changes as they move towards decarbonizing mobility, including through strategies that involve promoting active mobility.
Practical recommendations for general prac-titioners regarding physical activity and nutrition were drawn up by the USPSTF in 2017. These suggest approaching behavioral changes in the two areas for non-obese patients who also display no known risk factors (recommendation level C).100 While the studies identified show benefits on cardiovascular risk factors, no clarifications are made regarding active mobility, nor specifically regarding cycling, and there are of course no estimates about the environmental impact of these behavioral changes. These recommendations are currently being updated.101
A systematic review conducted 10 years ago showed that interventions aimed at inciting people to use bikes more might be more effective through individual promotion rather than wider campaigns. The authors nonetheless emphasized that there was a lack of studies allowing them to evaluate the scale of the change.102 Another review, published in 2011, underlines the importance of combining interventions that are geared towards changing individual behaviors with community action.103 Figure 6 illustrates, through an example related to cycling and bike lanes, how individual and structural measures can allow us to approach this question from a co-benefits angle.
Furthermore, we offer a summary of the overall approach to promoting active mobility, as illustrated in Figure 7.
• In Switzerland, motorized mobility is responsible for 30% of greenhouse gas emissions.
• Car trips require 50 to 300 times as much space as any other mode of locomotion (walking, biking, public transport, etc.).
• Motorized mobility has many harmful effects on human health: air and noise pollution, traffic accidents, sedentary lifestyles.
• Sedentary lifestyles are one of the primary risk factors for non-communicable diseases.
• Encouraging active mobility (walking, biking) for short journeys instead of motorized vehicles would allow to add on many health years for people, all while limiting atmospheric pollution.
• In Switzerland, over 60% of trips last less than 5 km. That distance is typically considered accessible on a mechanical bike.
• Two-thirds of the population would be in-terested in using bikes on a regular basis if the infrastructure allowed for it (bike lanes).