From the weather to the actions of other drivers, you’re faced with hundreds of variables that could affect your safety every time you hit the road.

In good health, most of us have the physical and mental capacity to steer ourselves away from danger. But when your body or mind is affected by a medical condition, your safety and the safety of others could be compromised.

It’s an unfortunate reality; drivers with serious medical conditions can be key factors in serious crashes.

In South Australia, both you and your doctor are required to report any medical condition that could impair your ability to drive a car safely to the Registrar of Motor Vehicles. If you don’t, the maximum penalty is a fine of $750.

There are a wide range of medical conditions that could impact your ability to drive; we’ve listed 6 below.

1. Dementia

Driving is a hugely complex task involving interactions between your eyes, brain and muscles. Tragically, dementia takes its toll on all of these functions, decreasing reaction time, memory, hand-eye coordination and spatial awareness.

Behind the wheel, dementia sufferers may find themselves travelling slower than the speed limit, becoming lost in familiar areas, confusing left and right turns, taking longer to react or braking/accelerating at the wrong time.

If you’ve been diagnosed with dementia, you’re required by law to inform the Registrar of Motor Vehicles. A doctor will assess your fitness to drive and you may be required to take a formal driving assessment.

2. Sleep apnoea

In 1999, a Spanish study exploring the association between sleep apnoea and the risk of traffic accidents found participants with sleep apnoea were 4–7 times more likely to be involved in a crash than non-sufferers.

A study by the Eastern Virginia Medical School using electro-encephalography and eye closure measurement showed sleep apnoea sufferers had a similar level of impairment to people driving under the influence of alcohol.

If you suffer from sleep apnoea, visit a doctor for further investigation and treatment. If you’ve had crashes caused by fatigue or if you represent a significant driving risk as a result of a sleep disorder, you may be deemed unfit to drive.

Participants with sleep apnoea were 4–7 times more likely to be involved in a crash than non-sufferers.

3. Cardiovascular conditions

Cardiovascular conditions can severely impact your ability to drive.

People suffering from heart conditions are at risk of suddenly becoming incapacitated – stressful situations on the road could lead to heart-related issues like breathlessness, palpitations and chest pain.

A range of short and long-term driving restrictions apply to people recovering from cardiovascular-related surgeries. These range from a 2 week restriction after the insertion of a cardiac pacemaker to a 6 month restriction following a cardiac arrest.

4. Psychiatric conditions

Mental health conditions can affect your cognitive, emotional and behavioural functioning which in turn, can impact how you drive.

When assessing the impact of mental illness on ability to drive, health care professionals often use the mental state examination (MSE).

According to the National Transport Commission’s medical standards for licensing and clinical management guidelines, a person will be deemed unfit to hold an unconditional licence if they have a chronic psychiatric condition so severe it impairs the insight, behaviour, cognitive ability or perception required for safe driving.

A conditional licence may be considered by the Registrar of Motor Vehicles subject to periodic review.

5. Epilepsy and seizures

If you’re diagnosed with epilepsy, it’s your legal responsibility to notify the Registrar of Motor Vehicles in your state or territory.

Epilepsy is defined as the tendency to experience recurrent seizures, though it’s important to note, not everyone who experiences seizures has epilepsy.

Not all seizures or seizure types will pose a risk for driving. Though rules are different in each state, whether or not you can keep driving after having a seizure will depend on a range of key factors.

To find out whether or not you can drive, your doctor will investigate the cause of your seizures, the type of seizure you’ve had and how long it’s been between your seizures. The Registrar of Motor Vehicles will determine the length of any restriction that may be required.

Not all seizures or seizure types will pose a risk for driving.

6. Eyesight

If you’ve got a diagnosed eye condition like glaucoma or macular degeneration then you’ll need an assessment from an optometrist to certify you’re fit to drive.

If you wear glasses or contact lenses for other vision problems you won’t need a full assessment.

If, however, you or your optometrist think your vision may affect your ability to drive safely, you’re legally required to report it in writing to the Registrar of Motor Vehicles at GPO Box 1533, Adelaide SA – and it may be ordered as a condition on your licence.

Find out more about eyesight requirements for driving.