Drive a lot? Here’s why you’re going to pay more to use Utah roads.

Utah is among states conducting early experiments on how to replace what they see as an increasingly broken gasoline tax system with a “road user charge” where drivers pay a fee for each mile they drive as a means to fund roads.

Also, Utah may soon charge drivers more — through both varying tolls and the new road user charge — to use crowded stretches at peak times, such as in Big and Little Cottonwood canyons on popular ski days. That may reduce congestion by pushing people to use mass transit instead.

Carlos Braceras, executive director of the Utah Department of Transportation, delivered those messages Monday at the Utah Taxpayers Association Legislative Outlook Conference before the 2021 Legislature convenes next week.

“I would say we are at the very tip of the spear” of experimenting with new road user charges, Braceras said.

He explained that more vehicles now escape gasoline tax or pay less because of either better fuel mileage or use of alternative untaxed power sources — such as electric or hybrid cars. UDOT has said the gasoline tax has lost 70% of its buying power in the last 16 years because of fuel-efficiency gains and construction cost inflation.

Last January, Utah became the first state in the nation to offer a voluntary road user charge program for owners of electric or hybrid vehicles. They pay 1.5 cents per mile traveled up to a maximum that matches the recently increased vehicle registration fees they would otherwise face. Mileage is measured by such means as a transponder plugged into the car.

Even if drivers pay the maximum they would otherwise be charged, Braceras says they can spread it out in monthly payments instead of paying it all at once when they renew registration. He reported that 3,648 Utah drivers voluntarily joined that program last year.

Braceras said the state is learning plenty through that pilot program, and will incorporate that into a plan the Legislature has ordered by the end of June on how to use such fees to completely replace gasoline tax here by the end of 2031.

One of the lessons is that it may not be wise to place such arbitrary deadlines, Braceras said, and instead use triggers based on technology improvements, fleet transformation to alternative fuels and increases in fuel efficiency.

He said the state has learned that drivers may need to be given a choice of several different means of reporting how many miles they drive based on evolving technology and varying capabilities of their current cars, from allowing a manual reading of odometers to plug-in transponders.

Braceras said as technology evolves, someday the state may be able to help reduce congestion through road user charges with higher fees during peak times or in places with congestion to encourage travel at other times.

“This is a path to the future for us: this idea of using price to attenuate demand or maybe help people make different choices,” he said.

UDOT increasingly plans to do that now, or soon, with expanded tolls, he said.

For example, tolls that allow single-passenger vehicles to use car pool lanes on Interstate 15 now vary according to how crowded traffic is — with much higher tolls during peak times. He said that will continue, and something similar is envisioned soon in Big and Little Cottonwood canyons to handle ski season traffic.

He notes that studies are now looking at enhanced buses, gondolas or even a cog train to help handle canyon traffic. But each of those mass transit options depends, he said, on toll charges to push people toward using them.

With variable tolls depending on congestion, “If the toll is pretty high, maybe I’ll take transit,” Braceras said. “We need to move a significant portion of people over to transit. We cannot fit another car up in the canyon.”