Does your driver and fleet safety policy make note of the effects of dehydration? In truth it’s not the most obvious of issues to address but research carried out by the University of Loughborough suggests that maybe it should be.

Heightened possibility of mistakes

The study, carried out by the University of Loughborough, published in the journal Physiology and Behaviour in 2014, suggests that drivers who are dehydrated are more prone to making mistakes. In fact, is suggests that the level rises to something akin to being over the drink drive limit.
Leader of the study, Professor Ron Maughan, said “We all deplore drink driving, but we don’t usually think about the effects of other things that affect our driving skills, and one of those is not drinking and dehydration.

“There is no question that driving while incapable through drink or drugs increases the risk of accidents, but our findings highlight an unrecognised danger and suggest that drivers should be encouraged to make sure they are properly hydrated.

“To put our results into perspective, the levels of driver errors we found are of a similar magnitude to those found in people with a blood alcohol content of 0.08%, the current UK legal driving limit. In other words drivers who are not properly hydrated make the same number of errors as people who are over the drink drive limit.”

How was the study conducted?

Results of the study were measured following a range of tests carried out over two days on male drivers using a laboratory-based driving simulator.

The test included a two-hour continuous and monotonous journey on dual carriageway. The trip encompassed bends, slow moving traffic that needed to be overtaken, rumble strips and a hard shoulder. On one day drivers were allowed 200ml of fluid every hour, and on the dehydration test day, only 25 ml an hour. During the normal hydration test there were 47 driving incidents, but when the men were dehydrated, the number rose to 101. The error rate also increased during the two-hour period, peaking in the last quarter.

The effects of dehydration were seen through changes in mood, reduction in concentration levels, decreases in alertness and impaired mental functioning. The research team responsible for the study stated that mild dehydration could produce negative changes in mood and reductions in concentration, alertness and short-term memory, as well as headache and fatigue. Industry figures suggest that 68% of all vehicle accidents in the UK are the result of driver error. It’s also thought that these results can be made worse during warmer weather with conditions in hot cars exacerbating the problem, especially with drivers who resist water intake to alleviate the need for toilet stops on long journeys.