Hypoglycemia and Driving

People with type 1 diabetes (T1D) must be aware of hypoglycemia as a potential risk when driving a vehicle. Some symptoms of hypoglycemia can alter cognitive skills, and untreated hypoglycemia can lead to unconsciousness. This is undeniably a serious and dangerous situation, particularly when driving is involved.

A common occurrence

According to a recent study, 1 out 5 people with diabetes had a hypoglycemic episode while driving in the past year. Low, or borderline low, blood sugar is a generally harmless situation when treated properly (i.e., by ingesting 15 grams of fast-acting carbs, resting and measuring blood sugar after 15 minutes). But since it’s more difficult to follow these steps while driving, it’s better to prevent hypoglycemia BEFORE driving.

However, 58% of participants in the study said they never measured their blood sugar before driving.

Risk factors for hypoglycemic episodes while driving

The study mentions two risk factors for developing hypoglycemia while driving:

  1. Living with T1D
  2. Hypoglycemia unawareness. The risk for a person who is unaware that their blood sugar is already trending low when they start driving is that they could start feeling their symptoms only once the hypoglycemia has reached a serious level, getting behind the wheel them on the brink of severe hypoglycemia and unconsciousness.

Did you know that it is mandatory for any person living with diabetes in Quebec to declare this fact to the SAAQ (Société de l’assurance automobile du Québec) and to report any change in their state of health?

This declaration must be made:

  • When first applying for a driver’s licence
  • Or when renewing a licence
  • Or within 30 days of a change in state of health

If you’ve never made this declaration, you must contact the SAAQ to do so. You’ll receive a form to be completed by your doctor at your next appointment. An eye exam will also be required. However, if your blood sugar control is not very good and you frequently have severe hypoglycemia, your doctor might want to wait until your blood sugar levels are more stable before signing the form. 

Tips for preventing hypoglycemia at the wheel

Here are a few suggestions to help all people with T1D drive safely.

  • Always measure your blood sugar before driving and treat any hypoglycemia before leaving. The SAAQ also recommends eating a protein snack.  
  • Bring your blood sugar meter in the car or, if possible, use a continuous glucose monitoring (CGM) system with low blood sugar alerts.
  • If you’re going on a long trip, plan to take breaks and measure your blood sugar. If you use a CGM, set your low blood sugar alerts to a higher level.
  • Always carry fast-acting carbs with you and in the car; make sure you have enough to treat two hypoglycemic episodes.
  • If you don’t feel well, stop on the side of the road.

Happy and safe driving!

The BETTER project aims to study how people with type 1 diabetes in Quebec manage their blood sugar.

If you wish to participate, sign up for the BETTER registry.


  • Lohan, L., Clément, F., Duflos, C., Villiet, M., Castet-Nicolas, A., Boegner, C., Breuker, C. (2020). Hypoglycemia While Driving in Insulin-Treated Patients: Incidence and Risk Factors. Journal of Patient Safety, Publish Ahead of Print. doi:10.1097/pts.0000000000000764

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