Driving with T1 diabetes

You need to take extra care when driving if you have Type 1 Diabetes (T1) or take insulin for type 2.
- You must inform the driving authority if you are treated with insulin or sulphonylurea tablets. In Ireland, you don’t need to tell them if you take any other type of diabetic tablets or are treated with diet alone. If you live elsewhere check the regulations in your country. In Ireland, the driving authority is the National Driver Licence Service.
- Check the following links for information for drivers with diabetes who live in Ireland: NDLS and RSA. Medical Fitness to drive guidelines were updated in August 2019 to change the regulations around glucose monitoring for class 1 driver only.
- You must also inform your insurance company that you have diabetes. Failure to do so is illegal and will leave your policy invalid.
- Always carry T1 identification with you when driving. If you have an accident, paramedics need to know that you have diabetes.
- Ensure that your blood glucose (BG) level is stable and always check it before driving, even for short journeys.
‘Never drive under 5 mmol/L (90 mg/dl)’
- I have often had to eat or take glucose before I drive even though I am not hungry. Glucose levels have to be 5 mmol or greater before driving. Even 4.9 mmol isn’t OK. It’s annoying to have to delay a journey but better safe than sorry and it’s the law. Experience has thought me to plan for it rather than often running late. Of course the best way is to keep glucose level in the driving range, but that is impossible. Most people’s lower range is 4 mmol, which means that 4.6 mmol is fine for pottering around at home or while at work but not for driving. Knowing what the level is a while before driving enables changes to be made in time for glucose levels to come up to 5 mmol before driving.
- Remember this doesn’t just affect your journeys from your house. When you are out and about whether for business or pleasure you should ensure that your BG is 5 mmol/L (90 mg/dl) or a little over before you sit into your car to drive home. A pain when you finish work and find your BG at 4.8 mmol and you have to take a glucose tablet or two and wait………….
- If you allow your blood sugar to drop to an unsafe level while driving it can lead to a loss of concentration, poor driving decisions and if left untreated a loss of consciousness, which can cause a serious road accident causing injury or death. A high blood sugar level over a period of time can cause tiredness, blurred vision and confusion, so is equally dangerous.
- Driving with a low blood glucose is exactly the same as driving while under the influence of alcohol or illegal drugs.
- Always keep glucose drinks or tablets in the glove box and some within easy reach too. Make sure they are replenished when you use them.

- On long drives you should stop and test your BG often and take any necessary action. Take your insulin and meals around the same time as you usually do.
- If you notice symptoms of a low BG, pull over straight away. You must remove the keys from the ignition and move from the driver’s seat. That is the law. If you remain in the driver’s seat the police can charge you with driving under the influence of a drug (insulin).
- Take a quick acting glucose drink or tablets. Glucose works quicker than sugar, sugary drinks or sweets. So unless you want to sit around all day waiting to drive (and possible cause complications from staying too long in hypoglycemia if your BG is under 4mmo) take the glucose! I like Dextrose Energy (3g of carb each) or Lift fast acting glucose chews (3.7g carb each). Know the quantity that will give you the increase that you need. If you use an insulin pump you may decide to suspend your insulin as well as taking glucose until your glucose level returns to normal. Always follow your medical practitioners advice. See my blog on hypos: http://theartisandiabetic.ie/hypoglycemia-hypo/
- Retest after 15 minutes. If you BG hasn’t returned to normal, repeat your dose of quick acting glucose. Wait another 15 minutes and retest. When your BG level returns to normal it can take longer for your brain function to recover. When your BG level is low (hypo) your brain isn’t getting fuel. When your blood glucose returns to normal and starts fuelling your brain again it can take up to 45 minutes for it to be fully functioning. Allow yourself the time to recover fully. This will depend on you as an individual, how low your BG is and other influences like your last meal, insulin dose etc. It may be necessary to eat a carbohydrate snack after treating a low BG, depending on whether you take insulin injections or use a pump.
- If you realise your low BG is unlikely to be treated quickly (e.g. you accidently gave a lot of insulin or overlapped insulin) it is best to make alternative plans for your journey. It’s better to let people know that you will be late than to put your own and other road users at risk by rushing your recovery.
- If you have changed your insulin dose/type, diet, routine, are tired or under stress particular care is needed while driving. All of these can lead to unstable BG levels, so test more frequently and take action if necessary.
- Stay hydrated by drinking plenty of water.
- Before driving on long journeys the best meal compilation is plenty of vegetables or salad combined with:
- Slow release carbohydrates (oats, butternut squash, beans, legumes, wholemeal/multigrain bread).
- Lean protein (eggs, milk, cheese, yogurt, fish, lean meat, nuts)
- Good fats (avocado, egg yolk, salmon, trout, mackerel, nuts and seeds)
The above will provide you with good slow release energy to keep your body and brain in good driving mode.
- Plan and take plenty of rest breaks on long journeys.
- If you don’t feel hypoglycemia (hypos/low BG) coming on you shouldn’t drive until such time as you have discussed this with your medical practitioner, taken action to improve your hypo awareness and your hypo awareness returns.
- If you needed another person to assist you in treating a hypo (you were unable to treat yourself) you should check if you need to inform your driving licence authority.
- You should have regular eye tests and don’t drive if you notice any vision issues until you check this with your Dr or Optician.
- Above all, drive safely.