When people think about what makes a safe driver, they usually think about physical things: good eyesight, fast reflexes, the ability to steer and brake. But the reality is that driving is primarily a cognitive task. The thinking skills behind the wheel matter far more than most people realise.

This is why the cognitive assessment is often the most important part of an OT driving assessment, particularly for people with conditions like dementia, stroke, brain injury, or Parkinson's disease.

This article explains what cognitive skills driving actually requires, and what the OT is looking for during the assessment.

Why driving is a cognitive task

Consider what happens in a single 10-second window at a busy intersection:

You're approaching a green light. You check your speed. You scan the intersection for vehicles, pedestrians, and cyclists. You notice a pedestrian stepping off the kerb to your left. You check your rear-view mirror. The light turns yellow. You calculate whether you can stop safely or need to proceed. A car to your right begins to edge forward. You decide to brake. You apply the brake with appropriate pressure. You check your mirror again. You come to a stop.

All of that happens in seconds, largely without conscious effort for an experienced driver. But every single step involves a cognitive skill: perception, attention, processing speed, decision-making, spatial awareness, memory, and motor planning.

When a medical condition affects one or more of these cognitive skills, the whole chain can break down, sometimes in ways the person doesn't even notice.

The key cognitive skills involved in driving

Attention

Driving requires several types of attention, all working at once.

Sustained attention is the ability to stay focused over time. A drive might last 20 minutes or two hours. If your attention drops, you miss things: a changing traffic light, a car braking ahead, a child running toward the road.

Selective attention is the ability to focus on what matters and filter out what doesn't. The driving environment is full of information (signs, buildings, parked cars, trees, other vehicles), and you need to identify the relevant hazards and ignore the rest.

Divided attention is the ability to manage multiple tasks at once. Driving constantly requires this: monitoring speed while checking mirrors while watching the road ahead while preparing to turn while processing your passenger's conversation. When divided attention is compromised, something gets dropped.

Shifting attention is the ability to move your focus between tasks as needed: from the road ahead to your mirrors, from the speedometer to a road sign, from monitoring traffic to responding to an instruction.

Conditions that commonly affect attention include stroke, brain injury, dementia, ADHD, and fatigue-related conditions like multiple sclerosis.

Processing speed

Processing speed is how quickly you can take in information, make sense of it, and respond. In driving, this matters constantly: seeing a brake light and responding, noticing a speed sign and adjusting, recognising a hazard and acting.

Slower processing speed means longer reaction times, which means less margin for error. At 60 km/h, your car travels about 17 metres every second. A delay of even one second in responding to a hazard adds 17 metres to your stopping distance.

Processing speed is commonly affected by stroke, brain injury, dementia, Parkinson's disease, and some medications.

Decision-making and judgement

Every few seconds behind the wheel, you're making a decision: proceed or wait, accelerate or brake, change lanes or stay, give way or go. Most of these decisions are small and automatic. But each one requires you to assess the situation, weigh up the options, and choose correctly.

Poor decision-making in driving shows up as:

• Pulling out into gaps that are too small

• Not slowing down for changing conditions (rain, school zones, narrow roads)

• Taking unnecessary risks (overtaking when it's not safe, running yellow lights)

• Failing to respond to unexpected situations appropriately

Decision-making can be affected by dementia, brain injury (particularly frontal lobe injuries), and conditions affecting executive function.

Spatial awareness and visuospatial skills

Spatial awareness is your understanding of where things are in relation to each other, and to you. In driving, this includes:

• Knowing where your car is within the lane

• Judging the distance between your car and the one ahead

• Estimating whether a parking space is big enough

• Understanding the layout of an intersection

• Judging speed and distance when merging or turning

Visuospatial difficulties can cause lane positioning errors, misjudged turns, clipping kerbs, or difficulty navigating complex road layouts like roundabouts or multi-lane intersections.

These skills are commonly affected by stroke (particularly right-hemisphere strokes), dementia, and Parkinson's disease.

Memory

Driving relies on both short-term (working) memory and long-term memory.

Working memory keeps information active while you're using it: remembering the speed limit you saw 30 seconds ago, holding a set of directions in your head, tracking the movements of several vehicles at once.

Long-term memory stores the knowledge you need: road rules, the meaning of signs, how to operate the vehicle, and your usual routes.

When memory is significantly affected (as in dementia), a driver may forget where they're going, miss familiar turns, or fail to apply road rules they've known for decades.

Insight and self-monitoring

This is perhaps the most important cognitive skill for driving safety, and the most difficult to assess.

Insight is your ability to recognise your own mistakes and limitations. A driver with good insight notices when they've made an error, corrects it, and adjusts their behaviour. A driver with poor insight may make the same error repeatedly without recognising it, or may believe they're driving safely when they're not.

Poor insight is particularly common after brain injury and in dementia. It's one of the main reasons an independent OT assessment is important: if someone can't accurately judge their own driving, they need an objective evaluator.

What the OT is doing during the cognitive assessment

During the off-road part of an OT driving assessment, the OT uses validated tools to assess these cognitive skills. These tools give the OT measurable data about your cognitive function. But the off-road assessment is only part of the picture. The critical question isn't "how do you perform on a test in a quiet room?" It's "how do your cognitive skills hold up when you're actually driving?"

That's why the on-road assessment is essential. The OT combines both sets of information to form a complete clinical picture.

Why cognitive changes can be hard to notice

One of the challenges with cognitive changes is that they're often invisible, both to the person experiencing them and to those around them.

A physical change (like a weak arm after a stroke) is obvious. A cognitive change (like slower processing speed or reduced divided attention) may only show up in high-demand situations, and driving is one of the most cognitively demanding everyday activities there is.

This is why families sometimes report that their parent "seems fine at home" but is having near-misses on the road. The cognitive demands of daily conversation, watching television, or preparing a meal are much lower than the demands of navigating traffic.

It's also why a doctor's consulting-room assessment can miss driving-relevant cognitive issues. Sitting in a quiet room answering questions is a very different cognitive environment from driving through a busy intersection. The OT assessment bridges this gap by testing cognitive skills and observing how they translate to actual driving.

When to consider an OT assessment for cognitive concerns

An OT driving assessment may be appropriate when:

• A medical condition has been diagnosed that is known to affect cognition (stroke, brain injury, dementia, Parkinson's disease, multiple sclerosis)

• Family members have noticed driving changes that may be related to cognitive decline

• A person is recovering from an illness or injury and it's unclear whether cognitive function has returned to a driving-safe level

• A doctor has identified cognitive concerns during a routine medical review (such as the annual medical assessment for drivers over 75)

• A learner driver has a condition that may affect the cognitive skills needed for driving (such as autism, ADHD, or intellectual disability)

Your GP or specialist can provide a referral. The doctor will complete the Transport for NSW Fitness to Drive form and refer you for the assessment.

Getting started

If you or a family member have concerns about cognitive changes and driving, the first step is a conversation with your GP. If a referral for an OT driving assessment is appropriate, you can start the process at steerdriving.com.au/referral.

Ready to book an OT driving assessment in Sydney? Steer Driving is a mobile assessment service covering greater Sydney. Whether you already have a referral or you're just getting started, get in touch and we'll guide you through the next steps.

This article was written by Elise, an AHPRA-registered Occupational Therapist and Transport for NSW-registered driver assessor. Elise is the founder of Steer Driving, a mobile OT driving assessment practice in Sydney.

FAQ Section

What cognitive skills does driving require? Driving requires sustained, selective, divided, and shifting attention, processing speed, decision-making, spatial awareness, memory, and insight (the ability to recognise your own errors). Most driving errors related to medical conditions trace back to one or more of these skills.

Why does the OT test cognition during a driving assessment? Because driving is primarily a cognitive task. The OT uses validated tools to assess the thinking skills most relevant to driving, and then observes how those skills translate to actual on-road performance. Both parts are needed for a complete picture.

Can someone pass cognitive tests but still be unsafe to drive? Yes. Cognitive tests in a quiet room don't replicate the real-time demands of driving. Some people perform well on tests but struggle on the road, which is why the on-road assessment is an essential part of the evaluation.

What conditions commonly affect driving-related cognitive skills? Stroke, brain injury, dementia, Parkinson's disease, multiple sclerosis, ADHD, and some medications can all affect the cognitive skills needed for safe driving. The impact varies from person to person.

How can I tell if a family member's cognitive changes are affecting their driving? Warning signs include getting lost on familiar routes, confusion at intersections, delayed responses to traffic changes, difficulty managing multiple tasks while driving, and not noticing or correcting their own mistakes. If you're concerned, raise it with their GP.