HOW much would a motorist be willing to pay to avoid congestion on the roads? Or, if you prefer public transport, how high would you go for a seat on that bus or train to work?

Just about double whatever it takes now to get a smooth ride, it seems, according to a new survey commissioned by the Land Transport Authority (LTA).

LTA economist Raymond Toh presented the findings at the ongoing World Roads Conference, although he made clear that these values had no direct link to bus or train fares or road tolls.

The survey of 4,000 respondents - 40 per cent were motorists and the rest public transport commuters - was meant to help transport planners gauge what motorists and commuters are willing to pay to save time.

'Ultimately, it gives us a better gauge of passenger behaviour in different scenarios to better plan future projects,' said Mr Toh.

The findings also showed that commuters and motorists here valued their time as much as their counterparts in cities in Britain and the United States, where similar surveys were carried out.

Dr Lim Wee Kiak, head of the Government Parliamentary Committee for Transport, pointed out that the findings may not capture the views of all commuters, and the likelihood was that commuters from different economic backgrounds would peg different values to their time.

'Some people may want to pay twice as much for an empty train but others don't mind if it's crowded but cheaper. Having different options is an idea to explore,' he said.

How motorists react to a change in parking charges and petrol prices was also captured in the survey.

While a hike in parking charges would make motorists consider staying off the road, just as higher ERP charges would, this was not the case for petrol.

Motorists are more prepared to pay for higher petrol prices to keep driving, considering that the cost of owning a vehicle here is higher than pretty much anywhere else.

'Motorists may see petrol as a basic need to run their cars and have more tolerance when prices go up ,' said Mr Toh.

Dr Lim added that this may be because motorists perceive a 1 cent or 2 cent increase in the price of a litre of petrol as less significant than a $1 or $2 jump in ERP charges.

The survey findings also gave planners an idea of the profile of car owners:

- The average income of car owners is higher than the national average and four in 10 car owners have children who are younger than 15 years.

- If they were to make the switch to public transport, motorists were more likely to hop onto a train than a bus.

- Motorists here cover longer distances a year than those in several major cities, such as Hong Kong, London and Tokyo, do.

These findings will help planners get a better fix on what else they need to do to reverse the trend of falling public transport ridership.

The public transport mode share went down from 63 per cent in 2004 to 59 per cent last year. Meanwhile, there were 31 per cent more trips made by cars.

In particular, LTA is eyeing one category of trips made by motorists, which it believes can be made by public transport instead.

Journeys to pick up or drop a passenger account for about 8 per cent of all trips made by car owners.

National University of Singapore transport researcher Anthony Chin told The Straits Times that a survey he carried out had found that 35 per cent to 38 per cent of car owners were willing to switch to public transport only if it was more stable.

'This means it must be more dependable in the areas of travelling time, waiting time and information,' he said.