Elsewhere, a woman who has had a stroke drives her car with one hand using spinner knobs to steer and operates the indicators, wipers and lights with electronic switches.
They are among several innovative modifications to cars which are helping people stay on the road despite severe disabilities. The clever devices include left-foot accelerators and hand controls for brake and accelerator.
In WA, there are only a few of the drive-from-the-wheelchair vehicles in which the cost of modification alone is about $80,000.
Gerri Clay said people were driving with all sorts of physical and cognitive impairments that included head injury, stroke, spinal injury, multiple sclerosis, cerebral palsy, dementia, neuro-degenerative disorders, and loss of limb, hand or foot.
And the number of drivers with disabilities would certainly increase as the population aged, she said.
Nicki Longmire, project manager for disability equipment grants, said statistics showed that people with a disability were no more likely to be unsafe when driving than people without a disability.
"The issue is the ageing population and that people may have a changing situation that needs to be assessed to find out whether they can continue to drive safely," she said.
"That is particularly an issue with people with altered mental states such as early dementia or neurological conditions such as Parkinson's or multiple sclerosis."
One of the big stumbling blocks is access to appropriate assessment. "We have limited services available in WA," Ms Longmire said.
Ms Longmire said the assessment was carried out by an occupational therapist with postgraduate qualifications in driver assessment.
The finding of whether the candidate is fit to drive is relayed to their GP, who then makes a recommendation to the Department of Transport. However, the person may still be required to undergo a DoT driving test.
Another hardship for many people is the cost of the assessment and, for those who need them, the vehicle modifications.
The Disability Equipment Grants program helps defray the costs. Funded by Lotterywest, the program provides means-tested grants for assessments and vehicle modifications for eligible people.
But Ms Longmire said many people were not eligible and had to pay $350 to $500 for the assessment.
"It is a significant amount when the majority of people are probably on a pension," Ms Longmire said, adding that if people could not afford to be assessed they were likely to have their licence suspended or cancelled.
People with physical impairments are likely to need modifications to their vehicles while those with cognitive problems such as dementia, or neurological conditions such as Parkinson's might be issued with a licence that restricts them to driving in daylight hours, off freeways, or locally, such as to the shops or their doctor.
"Some people may have a disability that causes fatigue but if they are aware of their fatigue and monitor their driving habits accordingly, then they will not necessarily pose a risk," she said.
The disabilities that totally rule out driving include blindness and high-level spinal injury.
Ms Longmire travelled to the UK, Denmark and Sweden in June to look at innovation in providing services and designing modified vehicles for people with disabilities and would like WA to follow their lead.
"They all had a good, supported-driver assessment service where people had access to that assessment for little or no cost," she said. In the UK, the maximum they paid was $150 but the service was often free.
Some of the innovative modifications, available only overseas, included a car which can be steered with the left foot while the accelerator and brake are operated with the right foot.
In another advance, a car can be driven using a small, plate-size steering wheel that responds to fingertip pressure.