More detours or change to other means of transport
Changes in the behaviour of cyclists due to traffic risks, noise and exhaust smells
Study "Effects of Perceived Traffic Risks, Noise, and Exhaust Smells on Bicyclist Behaviour: An Economic Evaluation"
Active mode (walking, bicycling, and their variants) users are exposed to various negative externalities from motor vehicle traffic, including injury risks, noise, and air pollutants. This directly harms the users of these modes and discourages their use, creating a self-reinforcing cycle of less active travel, more motorized travel, and more harmful effects. These impacts are widely recognized but seldom quantified.
The study, published in January 2019, evaluates these impacts and their consequences by measuring the additional distances that bicyclists travel in order to avoid roads with heavy motor vehicle traffic, based on a sample of German-Austrian bicycle organization members (n = 491), and monetizes the incremental costs. The results indicate that survey respondents cycle an average 6.4% longer distances to avoid traffic impacts, including injury risks, air, and noise pollution.
Using standard monetization methods, these detours are estimated to impose private costs of at least Euro 0.24/cycle-km, plus increased external costs when travellers shift from non-motorized to motorized modes.
Conventional transport planning tends to overlook these impacts, resulting in overinvestment in roadway expansions and under investments in other types of transport improvements, including sidewalks, crosswalks, bikelanes, paths, traffic calming, and speed reductions. These insights should have importance for transport planning and economics.
The results of the research also showed that the perceptions of these effects are different and may change over time. For example, traffic loads in German cities, which are far from ideal for cyclists, were perceived as better than in other countries. Cyclists also expressed an awareness of exhaust emissions, possibly as a result of public discussions about diesel emissions and court decisions to restrict old diesel car models in cities.
In summary, the interviews confirmed the central importance of exhaust emissions for cyclist behaviour. These findings were used to design the quantitative part of the study.