Diabetes & driving

Drivers with diabetes are generally not more prone to accidents than other drivers according to most studies. However, there are case reports of serious accidents due to hypoglycaemia. In the DCCT study hypoglycaemia was the main contributing factor in 36% of the traffic accidents that the participants encountered during the 9 years of the study. In a Scottish study, 25% of the participants attributed their road accidents to hypoglycaemia. Of cases reported to British authorities, 16-17% of cases of collapse at the wheel were caused by hypoglycaemia in a person with diabetes. Although these studies exemplify an increased risk of traffic accidents in a small number of cases, the conclusion of a review is that, for the general population with diabetes, accident rates do not exceed the rates for drivers without diabetes. As a comparison, a ban on all young male drivers would be more effective in terms of improving road safety, but would represent a totally unacceptable restriction in the freedom of individuals.

You should check your blood glucose before driving and if it is below 4-5 mmol/l (70-90 mg/dl) you should eat something before beginning your trip. If you don′t experience hypoglycaemic symptoms at low blood glucose levels (hypoglycaemia unawareness) you are not fit to drive. Even if you feel quite capable of driving when your blood glucose level is 2.5 mmol/l (45 mg/dl), your reaction time will be too slow for safety. This has been shown to occur below the level of approximately 2.8 mmol/l (50 mg/dl). It will take a while after a hypoglycaemic episode before your reaction time is back to normal. In one study where the blood glucose was lowered to 2.7 mmol/l (48 mg/dl) the reaction time was still prolonged 20 minutes after the blood glucose level had returned to normal.