If you drive when you’re diagnosed with type 1 diabetes, you must notify the DVLA using the confidential medical form DIAB1. It’s possible that the DVLA might write to your doctor to check whether you should continue to drive.
The main concern is the possibility of you having a hypo while you are at the wheel, which could cause an accident. This could lead to you being charged for driving under the influence (of insulin), dangerous driving or driving without due care and attention. Even a mild hypo can affect your driving.
Legally you need to test your glucose 30 minutes before you start driving, and then every two hours of your journey. You don’t have to test before each journey if you are doing lots of smaller trips at one time, as long as you test every two hours.
You also need to make sure you have a hypo treatment and a snack with long-acting carbs in your car. If you feel your levels are low, stop driving as soon as it’s safe, remove the key from the ignition and get out of the driver’s seat. Don’t check your glucose level or treat your hypo while you’re driving. Once you’ve treated your hypo, wait for 15 minutes, recheck your blood glucose and eat some carbohydrate. When you feel completely normal, wait 45 minutes until you drive again.
If you are considering learning to drive, or have just been diagnosed with type 1, consider discussing your driving and blood glucose management routine with your healthcare team.
Continuous glucose monitoring/flash glucose monitoring and driving
Group 1 drivers (cars and motorcycles) can now rely on interstitial fluid glucose readings but you must carry a finger prick glucose meter with you.
The DVLA says:
“These systems may be used for monitoring glucose at times relevant to driving Group 1 vehicles. Users of these systems must carry finger prick capillary glucose testing equipment for driving purposes as there are times when a confirmatory finger prick blood glucose level is required.
If using an interstitial fluid continuous glucose monitoring system (flash or real time-CGM), the blood glucose level must be confirmed with a finger prick blood glucose reading in the following circumstances:
- when the glucose level is 4.0 mmol/L or below
- when symptoms of hypoglycaemia are being experienced
- when the glucose monitoring system gives a reading that is not consistent with the symptoms being experienced (eg symptoms of hypoglycaemia and the system reading does not indicate this).”
Note that Group 2 drivers (bus and lorry) are still legally required to test blood glucose.
Driving other vehicles
Being diagnosed with type 1 diabetes can also affect your entitlement to drive a minibus, coach, bus or lorry. You’ll need to fill out your medical questionnaire and report, then a specialist medical questionnaire you’re given by your diabetologist or GP. You’ll then need an appointment with an independent diabetes consultant nominated by the DVLA.
You also need to prove that you regularly check your blood glucose on a meter with a memory function and that you have not had a hypo that has needed the help of another person in the last 12 months.