An expansion of Perth’s park-and-ride facilities could hold the key to reduced peak-hour congestion on the city’s major roads.

But it would come at a price — more trains would be needed, fewer people would ride bikes to work and bus patronage would decline in some areas.

Park-and-ride facilities are generally carparks built around train stations. It means commuters can drive to the stations, park their cars and complete their journey by train.

New University of WA research by civil engineering student Mugundan Radhakrishnan found that expanding park-and-ride facilities — and guaranteeing motorists could always find a parking spot — made train use much more attractive.

And with more people catching the train, traffic volumes were substantially reduced on Perth’s freeways and major arterial roads.

“Park and ride has the potential to reduce the number of vehicles on major roads, increase public transport patronage from park and ride locations and be a more viable alternative to increasing bus services,” Mr Radhakrishnan said.

Play Video We tested bikes, electric bikes, buses, trains and cars from four locations across Perth in an Amazing Race-style competition to see which mode of transport will get you to the CBD fastest The West Australian Video We tested bikes, electric bikes, buses, trains and cars from four locations across Perth in an Amazing Race-style competition to see which mode of transport will get you to the CBD fastest

In his research, Mr Radhakrishnan compared existing park-and-ride facilities use — with a limit on the number of car bays available — to a scenario where there was no restrictions on car bay numbers.

The second scenario meant that some current park-and-ride facilities increased capacity up to 6000 per cent to match the demand.

“The results from the two cases could then be compared with each other to determine the impact on traffic volume on specific roads and patronage on train routes and bus routes,” Mr Radhakrishnan said. “Analysis of the data from the two model cases suggests that increasing park and ride causes an overall decrease in the traffic volume on the freeways and major arterial roads.

“There are however sections of roads — mostly smaller local roads — that see an increase in the traffic volume as more people start driving to train stations.”

He said it was important to consider all aspects of transportation as Perth’s population grew.

“Public transport in Perth accounts for less than 10 per cent of the total mode share,” he said. “As the Perth metropolitan area continues to sprawl, more households will be reliant on vehicles to be their primary source of transport.

“Unless changes are made, Perth is projected to have seven of the top 10 most congested roads in Australia by 2031.”

Mr Radhakrishnan worked with the Department of Transport and the Planning and Transport Research Centre, who provided modelling data and technical support.