Cycling Research Board Annual Meeting

Cycling has gained attractiveness in Germany in recent years, particularly in urban areas. According to the ‘Mobility in Germany’ survey, in major cities, the share of persons using the bicycle at least once a month rose from 51 to 53 percent between 2017 and 2023 (infas et al. 2025). At the same time, residents in large cities and metropolises in particular suffer from high heat stress in the summer, as densely built-up urban areas heat up particularly strongly during the day and hardly cool down at night. Consequently, so-called heat days—days with temperatures of 30 degrees Celsius and above—occur significantly more frequently in large cities than the German average (UBA 2024).
Research shows that seasonal fluctuations are more pronounced for cycling than for other modes of transport (Nobis 2019). Several studies have found that, when it comes to heat, cycling rates increase up to a certain optimal temperature, which may vary depending on the city or region. Once this temperature is exceeded, however, bicycle use declines again (Miranda-Moreno & Nosal 2011). Several cyclists report switching to the car in order to avoid extreme heat stress when cycling (Burghard et al. 2025). This means, heat can hinder the transition to sustainable urban mobility.
In the ‘Heat Bike’ project we investigate the influence of heat on cycling. For this, we analyse data from shared bikes and bicycle traffic counters for German cities in order to determine whether bicycle use declines in hot days. Additionally, we conduct a case study in Karlsruhe to explore how cyclists adapt to hot weather. Based on this, we analyse and develop strategies and solutions for cycling in extreme heat at the municipal level and assess their effectiveness.
In this contribution we will present first results and discuss the next steps in the project.