Cyclist exposure to the risk of car door collisions in mixed function activity centers: A study in Melbourne, Australia

• Published in: Traffic injury prevention 2018-02, Vol.19 (sup1), p.S164-S168
• Main Authors: Lawrence, Brendan M, Oxley, Jennifer A, Logan, David B, Stevenson, Mark R
• Format: Article
• Language: English
• Subjects: Accidents, Traffic - statistics & numerical data; Adult; Australia; Automobiles; Bicycles; Bicycling; Bicycling - injuries; Collisions; Environmental Exposure - statistics & numerical data; Exposure; Humans; Risk analysis; Risk Factors; Roads; Roads & highways; Traffic accidents & safety; Video data
• ISSN: 1538-9588; 1538-957X
• DOI: 10.1080/15389588.2017.1380306

The objective of this study is to describe key risks related to dooring collisions on roads in mixed function activity centers by examining video footage recorded onboard the bicycles of cyclists riding through this road environment. The study aims to enhance our understanding of the risk associated with cyclist door collisions on these roads and to provide a focus for future studies that aim to identify measures that enhance cyclist safety. The study measured 4 key risk exposures (per hour and kilometer), namely, on-street parked cars and 3 conditions associated with parked cars being accessed or egressed: door opened (a) after the cyclist passes (give-way event); (b) in the path of the cyclist without collision (obstruction event); and (c) in the path of the cyclist with collision (collision event). Exposure to the risk factors was measured using video footage recorded onboard the bicycles of adult cyclists (n = 25) as they rode through this road environment. The average speed of cyclists was also estimated from these video data and related to the measures of exposure. The cycling experiences of the participants were observed over 3 h 58 min and 84.0 km. On average, the sample was exposed to 1,166 parked car events per hour (55 per kilometer), 6.9 give-way events per hour (0.3 per kilometer), 2.3 obstruction events per hour (0.1 per kilometer), and no collision events. There were 9 instances of obstruction events. In most cases, the cyclist was clearly visible (n = 7; 77.8%) and modified his or her position to avoid the door (n = 8; 88.9%). Moreover, the door was opened by the driver in nearly all cases (n = 8; 88.9%), primarily to exit the vehicle (n = 4; 44.4%) or enter the vehicle (n = 3; 33.3%). The average speed of cyclists was 22.7 km/h (SD = 4.1 km/h), and average speed tended to reduce as exposure to parked car events increased. Cyclists seldom interact with a vehicle occupant accessing or egressing a parked car, yet a concerning proportion of these interactions involve the occupant opening the door in the path of the cyclist, rather than waiting for the cyclist to pass. This suggests that there is still considerable need to identify measures that increase the likelihood that a vehicle occupant will look for cyclists before opening the car door, particularly in road environments where longer-term solutions such as physical separation are not readily achieved.