Diabetes mellitus: assessing fitness to drive
Source: gov.uk (2025-11-07)

Advice for medical professionals to follow when assessing drivers with diabetes mellitus.

Diabetes mellitus

Information sent to drivers

Insulin-treated drivers are sent a detailed letter from DVLA explaining the licensing requirements and driving responsibilities. All drivers with diabetes must follow the information provided in ‘Information for drivers with diabetes’, which includes a notice of when they must contact DVLA (see Appendix E (https://www.gov.uk/guidance/appendices-assessing-fitness-to-drive#appendix-e-inf1882-leaflet)).

Insulin-treated diabetes

Adequate awareness of hypoglycaemia

The Secretary of State’s Honorary Medical Advisory Panel on Driving and Diabetes has defined adequate awareness of hypoglycaemia as being able to recognise symptoms in time to safely stop the vehicle.

The alarms on glucose monitoring devices should supplement, not replace the individual’s own awareness and active self-monitoring practices. They should be set at appropriate levels of above 4.0mmol/L while driving.

If a driver becomes dependent on these alarms to recognise low glucose, they must stop driving and notify DVLA.

Impaired awareness of hypoglycaemia

For Group 1 drivers, the Panel has also defined impaired awareness of hypoglycaemia as being unable to recognise when the glucose level is low or starting to fall, due to a total absence of warning symptoms.

Group 2 drivers must have full awareness of hypoglycaemia.

Severe hypoglycaemia

The law defines ‘severe’ as an episode of hypoglycaemia requiring the assistance of another person.

For Group 1 drivers, hypoglycaemia that happens during established sleep is no longer considered relevant for licensing purposes, unless there are concerns about the driver’s ability to recognise low glucose.

Group 2 drivers must report all episodes of severe hypoglycaemia requiring the help of another person, including sleep episodes.

Continuous glucose monitoring systems (CGM)

Drivers should use a device that is medically approved for non-adjunctive use, meaning it is approved for making treatment decisions based on CGM readings. This ensures the monitor meets the required safety and quality standards.

Group 1 and Group 2

These systems may be used for monitoring glucose at times relevant to driving in Group 1 and Group 2 vehicles. Users of these systems must carry a finger prick blood glucose meter as a backup. This is essential in case the CGM stops working or gives readings that do not match how the person feels (for example, symptoms of hypoglycaemia but no low reading shown).

For more details, see Appendix E (https://www.gov.uk/guidance/appendices-assessing-fitness-to-drive#appendix-e-inf1882-leaflet).

Group 1 and Group 2 requirements for insulin-treated drivers licensed on review

The Secretary of State’s Honorary Medical Advisory Panel on Driving and Diabetes has defined the glucose self-monitoring requirements for licensing as follows.

Group 1 car and motorcycle

Glucose testing must take place:
- at the start of the first journey
- at least every 2 hours during the journey
A maximum of 2 hours should pass between the pre-driving glucose test and the first glucose check performed after driving has started.

Applicants will be asked to sign an undertaking to comply with the directions of the healthcare professionals treating their diabetes and to report any significant change in their condition to DVLA immediately.

More frequent self-monitoring may be required with any greater risk of hypoglycaemia (such as physical activity or altered meal routine).

Group 2 bus and lorry

Glucose testing must take place:
- at least twice daily, including on days when not driving
- at the start of the first journey
- at least every 2 hours during the journey
A maximum of 2 hours should pass between the pre-driving glucose test and the first glucose check performed after driving has started.

More frequent self-monitoring may be required with any greater risk of hypoglycaemia (such as physical activity or altered meal routine). A bus or lorry driver may be licensed if they need to use more than one glucose meter with a memory function to ensure 4 weeks of readings while on insulin are available for assessment.

How DVLA checks diabetes management requirements for insulin-treated Group 2 bus and lorry licensing

DVLA takes the following measures to ensure the requirements are met for the licensing of insulin-treated Group 2 bus and lorry drivers. Applicants must:
- stop driving Group 2 vehicles when they commence insulin, until DVLA has made a licensing decision
- have a stable medical condition for at least one month before starting a driving licence application
- attend an examination every 12 months by an independent consultant specialist in diabetes
At the examination, the consultant will require sight of glucose self-monitoring records for the previous 4 weeks stored on the memory of a glucose meter.

Applicants will be asked to sign an undertaking to comply with the directions of the healthcare professionals treating their diabetes and to report any significant change in their condition to DVLA immediately.

Recurrent severe hypoglycaemia guidance

Advice for Group 1 drivers who have had 2 or more episodes of severe hypoglycaemia while awake in the last 12 months

✘- Must not drive and must notify DVLA.

DVLA will then carry out medical enquiries before a licensing decision is made.

Advice for Group 2 drivers after every episode of severe hypoglycaemia in the last 12 months

✘- Must not drive and must notify DVLA following all episodes of severe hypoglycaemia.

Severe hypoglycaemia whilst driving

All Group 1 and Group 2 drivers who experience an episode of severe hypoglycaemia whilst driving must not drive and must notify DVLA.

Impaired awareness of hypoglycaemia – ‘hypoglycaemia unawareness’

For Group 1 drivers, the Panel has also defined impaired awareness of hypoglycaemia as being unable to recognise when the glucose level is low or starting to fall, due to a total absence of warning symptoms.

Group 2 drivers must have full awareness of hypoglycaemia.

Diabetes complications

Visual complications – affecting visual acuity or visual field

Renal complications

Limb complications – including peripheral neuropathy

Temporary insulin treatment – including gestational diabetes or post-myocardial infarction

Diabetes treated by medication other than insulin

Severe hypoglycaemia

The law defines ‘severe’ as an episode of hypoglycaemia requiring the assistance of another person.

All Group 1 and Group 2 drivers who experience an episode of severe hypoglycaemia whilst driving must not drive and must notify DVLA.

Managed by tablets carrying hypoglycaemia risk

Managed by other medication - such medication includes Metformin, DPP-4 inhibitors (gliptins), SGLT2 inhibitors, GLP-1 agonists and non-insulin injectables

Diabetes managed by diet or lifestyle alone

Severe hypoglycaemia due to causes other than diabetes management

Examples include hypoglycaemia post-bariatric surgery or in association with eating disorders, and the restriction applies for both car and motorcycle, and bus and lorry drivers.

Severe hypoglycaemia

The law defines ‘severe’ as an episode of hypoglycaemia requiring the assistance of another person.

✘- If there are episodes of severe hypoglycaemia from any cause other than diabetes treatment driving must stop and the driver must notify DVLA.

Group 1 car and motorcycle

Glucose testing must take place:
- at the start of the first journey
- at least every 2 hours during the journey
More frequent self-monitoring may be required with any greater risk of hypoglycaemia (such as physical activity or altered meal routine).

Group 2 bus and lorry

Glucose testing must take place:
- at least twice daily, including on days when not driving
- at the start of the first journey
- at least every 2 hours during the journey
A maximum of 2 hours should pass between the pre-driving glucose test and the first glucose check performed after driving has started.

More frequent self-monitoring may be required with any greater risk of hypoglycaemia (such as physical activity or altered meal routine).

Pancreas transplant

Islet cell transplantation

Seizures provoked by hypoglycaemia

Seizures provoked by hypoglycaemia now require a period off driving due to the prospective risk of a further seizure.