Traffic and accidents: Are the risks too high?

Whereas it has been common practice to assume that behavioural change is the primary remedy for road accidents, in fact, big reductions can come from engineering the vehicle or the environment so as to remove the consequences of human error. Because of this, it makes little sense to speak of human error in isolation, and it is much better to tackle the human-vehicle-road system as an entity. This greatly increases the potential for progress. The question how to reduce the risks associated with road travel is pursued using two categories: in the first by identifying risks associated with the human-vehicle-road system, counting 'routine' human error as an integral part, and in the second by identifying the risks associated with 'non-routine' human error, defined as inexperience error and error of 'excess' (drink-driving, speeding, and other aberrant behaviours). The relationships between the measured risk and the underlying behavioural influences (deriving from factors such as inexperience, blood alcohol level, relative speed) provide a basis for differentiating between the categories. Work on the quantification of risk with respect to behaviours and road and vehicle design is described within this framework.