Integrating traffic safety and accessibility: Spatial equity impacts of city-wide speed limit reduction in Amsterdam

Several European cities have reduced city-wide posted speed limits to 30 km/h to enhance road safety, promote sustainable mobility, and improve liveability in cities. The trade-off between proven safety benefits and possible negative impacts on travel times and accessibility are however not fully clear. Therefore, this study examines the joint effects of introduction of the city-wide 30 km/h speed limit on the traffic safety and job accessibility by car in Amsterdam and the implications for spatial equity. An integrated accessibility framework was developed, integrating monetised travel time costs and safety costs in job accessibility metrics, based on an integrated crash risk-accessibility model. Scenario analysis was conducted, examining how speed limit changes affect job accessibility by car for different income groups. Results showed that accounting for safety costs significantly alters spatial distributions of accessibility, reducing overestimations of job accessibility by car in less-safe areas. Moreover, implementation of the city-wide 30 km/h speed policy positively influences overall job accessibility by car when both safety and travel time are considered. The spatial equity analysis highlighted that the policy benefits both high- and low-income residents, contributing to more equitable access to opportunities and reducing accessibility disparities across the city. These findings emphasize that the city-wide speed limit reduction policies can serve as an effective measure for balancing safety, accessibility for car users, and equity objectives in cities. By integrating safety and accessibility metrics, this study provided a comprehensive framework for assessing the broader impacts of speed management policies, supporting their role in promoting safer and more inclusive urban environments.