Sydneysiders are leading the push away from cars, with a 6 per cent increase in public transport use over the past year and a corresponding 6 per cent decrease in drivers.

But problems with the reliability and safety of public transport are still stopping other drivers who want to switch from leaving the car at home. Nationally three in five commuters drive to get to work or school, while one in five use public transport. Only one in 10 ride a bike or walk to work.

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Research, to be released today, shows Sydney commuters are the highest users of public transport nationally, with 26 per cent catching the train or a bus to work or school.

Battered by soaring petrol prices and peak-hour congestion, only 57 per cent of commuters now drive to work - the lowest proportion of any capital city.

But even so more than one-third of Sydney commuters (35 per cent) refuse to use public transport because it takes too long, almost four in 10 say it is unreliable (38 per cent) and one-quarter (25 per cent) say it is not available where they live, work or go to school.

About 7 per cent of Sydney commuters say they are worried about their safety on public transport.

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In Melbourne, only one in five braves the stretched public transport system, according to the survey by insurer AAMI.

But more than two-thirds of them said they would be happy to use public transport if services were more reliable, more frequent, and safer.

In Darwin, nearly 75 per cent of Darwin commuters drive to and from work or school - with the lack of availability and reliability cited as key reasons for not using public transport.

AAMI corporate affairs manager Mike Sopinski said high fuel prices, consecutive interest rate rises and sinking consumer confidence were contributing to a rethink in how people travelled in our cities.

He said there was also a growing concern for the environment among commuters.

"Forcing people's hands are fuel prices and the availability of fuel so governments will need to plan for that," he said.

"Over the next two to three years the use of motor vehicles will change and their attitude to daily commuting will change.

"Reports say the price of petrol is heading towards $2 a litre by the end of the year. This will force people into car pooling and into lighter vehicles." Click here for more news on the petrol crisis.