Driving a heavy goods vehicle (HGV) carries significant responsibility. You’re operating large, powerful machinery on busy roads, often for long hours, and your health affects not only your safety but also the safety of everyone around you. That’s why every HGV driver in the UK must pass a D4 medical examination before getting behind the wheel—and continue to meet these health standards throughout their career.
Whether you’re aiming for your first HGV licence or preparing for a renewal, this guide breaks down everything you need to know: what the HGV medical test involves, how to prepare, how often it’s required, and what steps to take if you encounter any issues.
You’ll need a Group 2 medical (the D4) if you are:
In short, any UK HGV driver—whether starting the licence process or renewing at the necessary intervals—must complete the D4 medical.
It’s important to remember that, as an HGV driver, you’re operating large, powerful vehicles on busy roads, often for long hours. Your health doesn’t just affect your own safety—it impacts everyone around you.
The HGV D4 medical is an official health assessment that ensures you’re fit to drive a heavy goods vehicle (HGV) safely.
This test is a legal requirement set by the Driver and Vehicle Licensing Agency (DVLA) and exists to protect:
Failing to keep your medical certificate up to date can result in fines, penalties, or even losing your licence. For more details, see our full guide to HGV driver regulations.
A UK HGV D4 medical usually takes around 30 minutes and is conducted by a doctor. The purpose is to ensure you meet the DVLA’s health standards for safe driving.
The assessment typically includes:
This thorough check helps keep you, other road users, and your livelihood safe.
Being well-prepared can make your D4 medical quick and stress-free. Here’s what to do:
1. Book your appointment
Schedule your D4 medical with an authorised clinician, GP surgery, or accredited provider. Ask whether they will submit the completed form directly to the DVLA for you.
2. Gather essential documents
Bring:
3. Bring supporting health information
4. Prepare physically
By following these steps, you’ll give yourself the best chance of a smooth, successful D4 medical and ensure your licence remains valid.
The frequency of D4 medical checks depends on your age and personal circumstances:
If you develop a medical condition that could affect your ability to drive between checks, you must inform the DVLA immediately. Failing to report changes can result in serious penalties.
In some cases, the DVLA may issue shorter-term licences for drivers with specific health conditions. When in doubt, consult the DVLA guidance or speak with an occupational health professional.
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The D4 medical is a formal assessment completed by an authorised clinician. The form and official guidance outline exactly what is required. Key areas of focus include:
Vision
Drivers must meet the Group 2 eyesight standard—able to read a number plate at 20 metres in good light, with corrective lenses if needed, and achieve the required visual acuity. If vision cannot be fully tested during the exam, an optician or optometrist must complete the eyesight section.
Blood pressure
Blood pressure is measured at the appointment. For Group 2 entitlement, a reading of 180/100 mmHg or higher is considered a serious risk and requires notifying the DVLA. Lower readings are assessed with medical judgment, and most drivers with controlled blood pressure pass.
Diabetes and glucose control
Diabetes is closely assessed. Drivers starting insulin or experiencing severe hypoglycaemia must stop driving and inform the DVLA. The rules vary depending on insulin use, oral medication, and complications like diabetic eye disease, with stricter requirements for Group 2 drivers compared to standard car licences.
Sleep disorders and daytime sleepiness
Conditions causing excessive sleepiness—such as obstructive sleep apnoea—must be declared. Moderate or severe cases with daytime sleepiness require treatment and medical clearance before driving can continue. Mild cases without sleepiness may not need reporting, but the rules are specific and must be followed.
Neurology, seizures, and epilepsy
Any history of seizures is taken seriously. The DVLA defines seizure-free periods and reporting rules depending on seizure type. Group 2 drivers often face longer disqualification or monitoring periods than car drivers, and specialist reports or ongoing review are usually required.
Mental health, substance use, and other conditions
The D4 form asks about significant psychiatric conditions, alcohol or drug misuse, stroke, cardiac events, and other health issues. DVLA guidance outlines which conditions are notifiable and the medical evidence required.
Additional checks
Clinics may also assess height and weight, review medications, and screen urine for glucose or other markers where clinically appropriate. Practices vary between clinics, but the D4 guidance explains what the examining clinician must record.
If you meet the required standards, the clinician will complete your D4 form, which you then submit with your HGV licence application or renewal.
If a medical condition needs further assessment, the DVLA may:
It’s crucial to notify the DVLA of any notifiable medical condition. Failing to do so while continuing to drive can result in fines of up to £1,000, licence revocation, and potential prosecution if an accident occurs. Always report changes promptly to stay compliant and safe on the road.
Certain health issues may prevent you from passing a D4 medical, including:
The standards are strict because the consequences of an unfit driver operating a 44-tonne vehicle can be severe.
If you have any concerns about your health, it’s a good idea to speak with your GP before booking your medical appointment.
Failing a D4 medical doesn’t necessarily mean the end of your driving career. Here’s the usual process:
With the right support and management, many drivers are able to return to the road safely.
Integrate medical checks into workflows
Include D4 medical assessments as part of recruitment and licence renewal processes. Require new drivers to provide a completed D4 and retain proof of current entitlement.
Educate drivers on their responsibilities
Make sure drivers understand their legal duty to inform the DVLA of any medical changes and the potential consequences of failing to do so.
Support driver health proactively
Encourage drivers to report symptoms early, particularly related to sleep disorders, diabetes, or heart conditions. Offering occupational health support can help catch issues before they affect safety or compliance.
Track medical expiry dates
Maintain records of medical certificates and set reminders for renewals. Many businesses use HR or fleet management systems to automate alerts.
Facilitate access to assessments
Providing access to occupational health services or accredited D4 clinics can speed up medical checks, reduce downtime, and help keep drivers on the road safely.
