Description of same-direction car-to-bicycle crash scenarios using real-world data from Sweden, Germany, and a global crash database

Journal article, 2022

The overall number of traffic crashes is decreasing, but the number of crashes incurring cyclist injuries is not decreasing at the same pace. Of all car-to-bicycle crashes, same-direction crashes are among the ones with the highest risk of a serious-to-fatal injury. In this study, car-to-bicycle crashes occurring when a passenger car and a bicycle are both traveling in the same direction and on the same road (without a physically separated lane) from four different real-world crash databases were investigated. The focus was on analyzing pre-crash factors such as speed and light conditions, as well as other factors such as impact configurations and cyclist injuries. Three main crash scenarios were identified among the crashes that were studied. The most common one (comprising 65%) was CS1: “continued same-direction” with no intention of turning by either road user. The other two scenarios were CS2: “the bicycle crosses the vehicle's path by turning” (16%) and CS3: “the car crosses the bicycle's path by turning” (19%). The CS1 crashes were divided into three overtaking phases: approaching and steering, passing, and returning, representing 42–44%, 41–44%, and 12–17%, respectively, of the CS1 scenario. The three crash scenarios varied in car and bicycle speeds, road type, and weather and light conditions, as well as in impact points and cyclist injuries. The analysis of different same-direction crash scenarios and overtaking phases in this study offers a novel view of same-direction crashes, providing relevant information for the design of methods for the evaluation of crash avoidance and injury mitigation measures for these scenarios.