Dooring

A cyclist in a bike lane situated in a door zone (left) is struck when a car door is opened unexpectedly (right)

Dooring is the act of opening a motor vehicle door into the path of another road user.^[1][2] Dooring can happen when a driver has parked or stopped to exit their vehicle, or when passengers egress from cars, taxis and rideshares into the path of a cyclist in an adjacent travel lane. The width of the door zone in which this can happen varies, depending upon the model of car one is passing. The zone can be almost zero for a vehicle with sliding or gull-wing doors or much larger for a truck. In many cities across the globe, doorings are among the most common and injurious bike-vehicle incidents.^[3] Any passing vehicle may also strike and damage a negligently opened or left open door, or injure or kill the exiting motorist or passenger.

Doorings can be avoided if the driver checks their side mirror before opening the door, or performs a shoulder check. Use of the Dutch Reach (or "far hand method") for vehicle egress has been advised to prevent doorings, as it combines both measures. As bicyclists cannot rely on motor vehicle occupants to use required caution on exiting, bicyclists are advised to avoid the door zone of stopped or parked vehicles.^[4]

The term is also applied when such sudden door opening causes the oncoming rider to swerve to avoid collision (with or without loss of control), resulting in a crash or secondary collision with another oncoming vehicle or another vehicle that is directly next to the cyclist. The term also applies when a door is negligently left open, unduly blocking a travel lane.^[5]