Older people should be encouraged to use public transport and other methods of getting around before they have to give up their driver's licence, research from the Monash University Accident Research Centre has found.

Australia will see an "explosion" in the number of drivers over the age of 65, making up 20 per cent of the people on the road by 2040.

Right now, about 70 per cent of older people use their car as their sole form of transport.

Only about 22 per cent walk or use public transport. Others do not walk because of fears about traffic and personal security.

Study author Dr Jennie Oxley said if those factors could be improved, the number of people participating in "active transport" like walking could increase.

"We do want to get older people to use alternative forms of transport before they get to that stage where they should give up driving," she said.

"If we can get them planning ahead, well that means a huge potential increase in alternative transport use."

Dr Oxley said everyone talked about retiring from work, but no-one spoke about retiring from driving.

"If you can plan ahead, make the decision yourself, with family, it's going to be much better psychologically," she said.

"We know if older drivers lose their licence... there's all sorts of depression, loss of self-esteem, loss of independence, because they haven't planned ahead.

"If we can get people to think about using alternative transport at an earlier age, they're much more used to it, so it's a smoother transition."

One of the ways to make the roads safer for the most vulnerable road users, like the elderly and children, was by cutting speed limits.

In strip malls they could be cut from 40 kilometres per hour to 30kph, Dr Oxley said.

"I believe if we can bring those travel speeds down we can save a lot of lives," she said.

Val Gallagher, 71, of Northcote, uses public transport to go into the city on a regular basis because it is easier than parking.

She hopes to be able to keep driving for years to come.

"My father drove to 93," she said.

"If I could make it to 93 that'd be great but I may have to give up earlier if I feel I can't do it any longer."