HealthInfo Waitaha Canterbury
Driving with diabetes
Te taraiwa me te mate huka
Driving is a complex skill, both physically and mentally. If you have diabetes, you may need to take extra precautions to make sure you're safe on the road.
Low blood glucose (hypoglycaemia)
If you take insulin or some types of diabetes tablets (not metformin), the main concern when driving is low blood glucose (hypoglycaemia or a hypo). This is where your blood glucose (sugar) levels drop too low. This is usually at a blood glucose level below 4 mmol/l, but some people can have symptoms with blood glucose levels a little above this.
Even mild hypoglycaemia can affect your ability to drive safely. If you do not do anything about it, hypoglycaemia can cause you to pass out. You need to be aware of the risks involved and plan ahead before you get behind the wheel.
Other risks when driving with diabetes
Hyperglycaemia (high blood glucose)
Very high blood glucose levels (hyperglycaemia) can also make you feel unwell or tired and may affect your ability to drive safely. You shouldn't drive if you're severely hyperglycaemic.
Long-term diabetes complications
Other concerns that can affect your ability to drive safely are the possible long-term complications of diabetes. These include eye problems, loss of sensation in your feet and heart problems.
Being newly diagnosed with diabetes
If you've just been diagnosed with diabetes and your treatment is still being adjusted, you may not be fit to drive just yet. Check with your general practice team or specialist.
How to avoid low blood glucose levels while driving
- Check your blood glucose level no more than two hours before driving. It needs to be above 5 mmol/l and stable before you drive.
- Always have a meal or snack before you set out on long trips.
- Carry a blood glucose meter with you when you drive.
- Travel with a supply of fast and longer-acting carbohydrate foods or drinks such as muesli bars, biscuits, glucose tablets, dried fruit or fruit juice.
- If you're driving for two hours or more, recheck your blood glucose level at least every 2 hours to make sure it stays above 5 mmol/l.
- If you're on a long trip, stop to rest and have something to eat and drink regularly.
What to do if your blood glucose level gets too low while driving
Many accidents caused by hypoglycaemia are because drivers have kept driving and ignored their hypo warning signs, such as hunger, sweating and feeling faint. If you feel that your blood glucose is low while driving, take the following steps:
- stop the vehicle when it’s safe
- switch off the engine and remove the keys from the ignition
- get out of the driver’s seat
- take some fast-acting carbohydrate, such as glucose tablets or sweets, and eat some form of longer-acting carbohydrate, such as a muesli bar or biscuits
- check your blood glucose level
- do not start driving until 45 minutes after your blood glucose level has returned to normal (above 5 mmol/l).
It may take up to an hour before your brain has time to recover.
When not to drive
- If you experience hypoglycaemia without warning signs (called hypoglycaemia unawareness), it may be unwise for you to drive. You should discuss this with your general practice team or specialist.
- If you have a severe hypoglycaemic episode, such as one that needs someone else’s help to deal with, you shouldn't drive for 24 hours.
- If you have several hypoglycaemic episodes, you should talk to your general practice team before you return to driving.
- If you have a severe hypoglycaemic episode while you’re driving, you shouldn’t drive for at least a month – whether you're involved in a crash or not. It’s likely that you’ll need to see a specialist before you can safely return to driving, and you’ll need to talk to your general practice team.
Licence conditions
Sometimes a driver with diabetes may be issued with a licence that has certain conditions attached. The conditions will depend on:
- your type of licence (classes and endorsements)
- how your diabetes is controlled
- whether you have any history of hypoglycaemic attacks
- how carefully you follow your medication schedule
- an assessment of how much you're affected by the common complications of diabetes.
The Waka Kotahi NZ Transport Agency decides your licence conditions.
Passenger services and heavy vehicles
People with type 1 diabetes are generally not considered fit to drive heavy trade vehicles, taxis, buses and other related vehicles. In exceptional circumstances, the Waka Kotahi NZ Transport Agency may grant a licence after consultation with your general practice team and diabetes specialist. If you're granted a licence to drive any of these vehicles, strict conditions are likely to be imposed.
Misusing diabetes medications while driving
Insulin and tablets for controlling diabetes are classified as drugs under the Land Transport Act 1998. This means you could be prosecuted under the Act if you misuse or abuse diabetes medications and your driving results in a crash or injury.
HealthInfo recommends the following pages
- Waka Kotahi NZ Transport Agency – Diabetes and driving
Information about the risks and legal requirements of driving with diabetes.
Content shared between HealthInfo Canterbury, KidsHealth and Health Navigator NZ as part of a National Health Content Hub collaborative. Last reviewed November 2022.
SourcesReview key: HIDIA-21832
