Effects of Urban Road Geometry on Vulnerable Road Users

Road geometry impacts the safety and mobility of Vulnerable Road Users (VRUs), particularly pedestrians and cyclists. This thesis studies the influence of specific design elements, such as intersection layout, lane width, and traffic calming devices, on travel speed, conflict points, and drivers’ behavior, which affect crash likelihood and injury severity for VRUs. The safety of pedestrians is highly influenced by the built environment. On a local scale, the three components that impact the safety of pedestrians are visibility, traffic volume, and traffic speed. The analysis includes accidents involving VRUs in urban areas, different safety indicators, countermeasures, accident consequences, and risk factors. In addition, different frameworks, including the safe system approach and zero vision, are introduced. The case study addresses designing a roundabout replacing a signalized intersection in the city of Bologna. The design aims to enhance the safety, connectivity, and overall livability of the area. The analysis considers the connectivity of the cycle lane to Bologna’s city center, the conflict points at the current intersection, and the accident record in the area between 2018 and 2023. Two potential cycle paths to connect the area with the city center were identified, both of which align with the planned cycle path by the municipality of Bologna. The design integrated traffic calming devices such as speed tables to maintain low travel speed and ensure safety for children and the elderly, considering the presence of a school and church in the area. Overall, the proposed design of the roundabout prioritizes the safety of VRUs and promotes soft mobility in the area.