A key principle of the Safe System is that humans make mistakes, but it is important to understand mistake making and be able to categorise into errors and violations. These are two forms of aberration which have different psychological origins and often demand different remediation. 

Back in the 90s, Reason et al., published work looking at errors and violations on the road and went a step further by categorising these aberrations into; violations, dangerous errors, and relatively harmless lapses. 

These categories were explained by noting that violations require explanation in terms of social and motivational factors, whereas errors (slips, lapses, and mistakes) may be accounted for by reference to the information-processing characteristics of the individual. 

A more recent Western Australian study by Blockey & Hartley repeated Reason et al.’s original study, and found young drivers committed more dangerous errors and dangerous violations than older drivers. Females reported more dangerous errors than males. Males reported more dangerous violations than females. Drivers who reported a high level of road exposure and those who reported having been convicted for speeding reported more dangerous violations.  

The video shows clear categories of violations, where drivers are using footpath and bike paths to avoid traffic.  


Blockey & Hartley, Aberrant driving behaviour: errors and violations, Ergonomics, 2007 

Reason Et Al, Errors and violations on the roads: a real distinction?, Ergonomics 1990.