The Science and Politics of Bicycle Driving

The Evidence against the Taboo (continued)

The common causes of car-bike crashes by teenagers and adults are listed in Table 2 below, adapted from Forester[4]:

The most common causes of car-bike crashes involve failure of cyclists to obey the vehicular Rules of the Road and consequently operating in an unpredictable manner. Particularly dangerous is wrong-way cycling which causes the most common crashes as shown in Table 2. Wrong-way cyclists approach intersections where motorists are not looking for vehicles, and the combined speed of the motor vehicle and bicycle makes avoidance more difficult and crashes more traumatic. Of those crashes that do involve lawful cyclists and are caused by motorist error, most are caused by turning and crossing actions, not overtaking. Visible and predictable operation as the driver of a vehicle at intersections prevents crashes caused by cyclists and maximizes cyclists' ability to avoid motorists' errors, while behaving as a pedestrian-on-wheels greatly increases the likelihood of being in one of the most common crash types listed in Table 2. 

Motorists-caused overtaking-type collisions amount to just 2% of all urban car-bike collisions in daylight, and about 0.3% of all accidents to urban daylight cyclists. However, overtaking-type crashes caused by motorists traveling at high speed in daylight are somewhat more likely to result in fatalities, resulting in much greater levels of public attention to a small number of crashes.  Besides maximizing their visibility and riding straight, there is little that cyclists can do to reduce this low probability of crash without increasing the likelihood of the much more common types of crashes at intersections. The best way to effect reduction of the rare motorist-error overtaking-type crashes is to recognize the typical causes, which are:

• Motorist impairment (drugs, alcohol, etc.)
  
• Extreme motorist negligence
  
• Reckless driving
  
• Motorist unfit to drive due to vision or health issues