Pedaling through a virtually redesigned city: Evaluation of traffic planning and urban design factors influencing bicycle traffic

To achieve the 1.5-degree target of the Paris Climate Agreement, it is of great importance to promote environmentally friendly means of transport. In urban areas, shifting motorized trips to active transport modes (i.e., walking and cycling) is essential. Therefore, knowledge of walking and cycling is indispensable for planning and policy, which is the basis for targeted promotion of active forms of mobility. This paper aims to identify factors that specifically influence cycling and to derive recommendations for action for planning and policy in a virtual testbed. Specifically, the influence of traffic planning measures (i.e., structural infrastructure facilities for stationary and moving traffic as well as traffic regulations) and urban design measures (i.e., the design of public space) on the promotion of cycling will be shown. For this purpose, a virtual reality simulation was used, independent of different external conditions during field surveys and the necessity of time-, cost- and regulation-intensive structural changes. Using an improved bicycle simulator, 93 people cycled through 20 variations of an approximately 680 m long road section, surveying the effect of selected traffic planning and urban design parameters. Special attention was paid to the subjective safety of the cyclists and the attractiveness of the urban environment. Furthermore, three types of infrastructure were differentiated: No bicycle infrastructure (riding on the roadway), a bicycle lane, and a structurally separated cycle path next to the sidewalk. The virtual road section represented a real location. In addition to the findings gained from the physiological optimization of the simulator, the results show that roadside greenery had the highest effectiveness in terms of subjective safety and attractiveness. Other factors with a high influence were a speed reduction from 50 to 30 km/h when riding on the roadway with cars and the red coloring of the bicycle lane, each increasing the perception of safety. In contrast, a lack of a boundary line between the cycle path and the sidewalk was unsettling for those who rarely or never ride bicycles in their daily lives. In addition, restaurant and recreation areas increased the attractiveness of the road section, although entailing a lower perception of safety. Other factors, such as motor vehicle traffic volume or vehicles parked at the roadside, showed no significant effects on the evaluation of cycling.

With the help of these findings, the consequences of traffic planning and urban design measures can be better assessed in subsequent virtual testbeds. Also, initial trends can be identified as to which planning instruments should be used as a priority to promote cycling in urban areas. Future work should validate the transfer of these insights into physical urban spaces to support further the mid-term transformation towards sustainable urban mobility using scientific evidence.