METRO VANCOUVER -- As Metro Vancouver residents wrestle with a 0.5-per-cent sales tax increase for transportation, regional mayors are preparing for an even bigger ask: a road pricing scheme that could potentially see tolls on all roads and bridges or charging drivers a fee-per-distance travelled.

What form the scheme will take has yet to be determined, but it is slated to come into effect five to seven years after the transportation plebiscite wraps up this spring.

But mayors acknowledge they could face a roadblock in their plans if voters reject the proposed sales tax.

“It doesn’t hinge on a Yes or No vote,” said Greg Moore, spokesman for the mayors’ council. “But if the first part of the plan doesn’t get funded, what do you do? The mayors are going to have to make that decision after we get through this referendum.

“We haven’t put any time or debate to this item.”

Metro mayors have long eyed road pricing as a long-term funding source to expand transportation across the region. The intent is that it would eventually replace existing fees such as the gas tax, which has seen falling revenues as vehicles become more efficient or drivers head out of the region or to the U.S. to buy cheaper fuel.

How it would work here remains to be seen, but mayors expect it would likely be a hybrid model based on systems in place in Singapore, London and Stockholm. Officials are also watching a pilot project in Oregon, set to start July 1, in which 5,000 drivers will be charged 1.5 cents per mile driven. The intent is to provide volunteers with a credit to offset the fuel tax they pay at the pump, but they may end up paying more depending on how much they drive per month and the average miles per gallon of their vehicle.

“It would have to be a made-in-Vancouver model here and likely related to distance, using bridges and tunnels as tolling points,” said North Vancouver District Mayor Richard Walton. “You can’t just use bridges because that penalizes people going east-west and not north-south.”

Congestion pricing, which is used in London and Stockholm, could work in downtown Vancouver but wouldn’t be effective across the region, Walton said. Such a model draws a circle around the downtown core, charging a fee every time a driver crosses through, but this means a driver could get from West Vancouver to Surrey without having to pay anything.

Singapore’s model, which has electronic road tolling on major arteries with motorists charged per distance travelled during peak hours, is probably the most suitable, Walton said, but notes the problem here is that TransLink doesn’t own all the roads and bridges across the region. This could pose issues for motorists as they pass through the different “gantries” that record entrances and exits.

The Port Mann Bridge and Massey Tunnel, for instance, are owned by the B.C. government, while TransLink has responsibility for the Pattullo, Knight and Golden Ears bridges and the city of Vancouver controls the Granville, Burrard and Cambie crossings. Various roads and highways are also shared among TransLink, municipalities and the province.