A study of 571 hospitalised drivers in New Zealand discovered that the chances of dying or being seriously injured leapt five fold between the hours of 2am and 5am.
The University of Auckland researchers also found that drivers who reported feeling sleepy were eight times more likely to end their trip in hospital, while driving after five hours or less sleep in 24 hours saw the chances of an accident rise three-fold.
The study concluded that if an end could be put to all three practices, there would be a 19% reduction in deaths and injuries on the roads.
The findings help support the Government's 'Think! Don't Drive Tired' campaign that has been running over the last couple of months.
In Fleet News recently, road safety organisation Brake called on the Government to devise a code of practice for employers on driver tiredness, and risk management assessment company Risk Answers made a plea to employers to make drivers aware of the dangers of driving when tired.