B.C. Liberal Leader Christy Clark and B.C. NDP Leader John Horgan made duelling promises today to leave more money in the pockets of Lower Mainland motorists.

Clark pledged that if her party is re-elected, it will introduce a $500 cap on annual road tolls on the Golden Ears and Port Mann bridges.

The B.C. Liberals also say that this cap will also apply to any future tolls on a new Pattullo or Massey crossing bridges.

Horgan went one step further, promising to eliminate tolls altogether on the Golden Ears and Port Mann Bridges.

In 2015, TransLink generated $48.4 million in toll revenue on the Golden Ears Bridge, which connects Langley with Maple Ridge. The Port Mann Bridge generated $136 million in 2015-16,

Residents of Langley and Maple Ridge were the most vehemently opposed to a 2015 transit and transportation plebiscite that would have brought substantial transit improvements to the region.

In Maple Ridge, 77.03 percent voted no. In Langley, 74.97 percent voted no.

In Surrey where many users of the Port Mann Bridge live, 65.54 percent voted no.

The $808-million Golden Ears Bridge opened in 2009, replacing the Albion ferry. The bridge was developed to bring Fraser Valley residents onside with transit and transportation infrastructure projects in other parts of the region. But this clearly didn't work.

The bridge was also one of several factors that contributed to a rising population in Maple Ridge. This, in turn, led to the development of a new $200-million Pitt River Bridge connecting Port Coquitlam and Pitt Meadows.

The tolled Golden Ears Bridge has been losing $35 to $45 million per year, whereas annual losses have been more than double that on the Port Mann Bridge.

B.C. Liberal politician Mike de Jong claimed that the cap on tolls will put more than $1,000 per year in the pockets of commuters who use the bridges.

Meanwhile, the Seattle-based Sightline Institute has been tracking the reduction in driving in the Pacific Northwest over more than a decade. It has sometimes poked fun at missed traffic forecasts by B.C. government analysts.

"The comedians in the Port Mann Bridge forecasting department are at it again: despite a 29 percent decline in traffic volumes on the Port Mann bridge between 2005 and 2014, the province is still predicting an immediate, sustained increase in traffic across the span," Sightline researcher Clark Williams-Derry wrote two years ago.

With the elimination or a cap on toll revenue, however, there is a distinct possibility that traffic will increase.

While that's not going to be welcomed by those suffering from respiratory illnesses such as asthma, it would increase gasoline-tax revenue to TransLink and the provincial government. And it might make the outer suburbs more appealing to real-estate developers in pursuit of cheap land upon which to build housing and shopping malls.

Neither Clark nor Horgan has ever served as a municipal politician and sat on the Metro Vancouver board. That's where a great deal of discussion has taken place over the years about demand-side measures to curb motor-vehicle use and free up roadspace for the movement of goods and services.

With their promises to cap or eliminate tolls, Clark and Horgan may have just created new headaches for the region's transportation planners: more traffic congestion and rising greenhouse gas emissions. But hey, there's an election to be won. So springing surprising new toll policies on the region should probably be expected.

The car dealers and lobby groups that benefit from their largesse will be thrilled.