The official system
STATS19 records details of reported injury collisions. Contributory factors were used through most of 2023 and are being replaced by road-safety factors.
The tiredness factor
Historic tables include fatigue or illness categories and factors such as tiredness. Read the table definition and year before extracting a number.
A changing time series
The Department for Transport warns that the move to road-safety factors affects comparability. Data initially recorded under the two systems are presented separately.
Not every collision is coded
Contributory factors reflect the attending officer’s assessment and are not assigned to every collision. They are not proof of clinical sleep or a complete fatigue count.
Where to obtain figures
Use the current RAS07 factor tables and the Department for Transport guide rather than copying an undated percentage from secondary articles.
EyeJolt boundary
EyeJolt is an alertness aid, not a road-safety system or evidence that a driver is fit to continue.
Sources
- UK Department for Transport: Road safety contributory factors
- UK Department for Transport: Road safety statistics tables
Written by the EyeJolt Editorial Team. Published and last reviewed 2026-07-14. Editorial policy.