NEW MEXICO (KRQE) – Fuel-efficient cars and electric vehicles might be good for New Mexico’s greenhouse emissions, but as drivers use less gas, the state’s funding source for road improvement is shrinking. So, lawmakers are considering new ways to pay for roads.

New Mexico’s Department of Transportation (NMDOT) oversees more than 100,000 lane-miles of roadways across the state. Keeping up with repairs is a never-ending task, and as some drivers know, a task that sometimes feels like it’s never completed in some areas.

The state relies heavily on the “gas tax” to keep up with road repair and maintenance. Per state law, 17 cents of every gallon of gasoline sold in New Mexico goes to the state and is re-distributed to local governments. The problem is that the $0.17 tax hasn’t increased for decades. Meanwhile, cars have been using less and less gas while the cost of roadwork, according to the Federal Highway Administration, has increased.

“The primary source for road funding is the gas tax,” NMDOT’s Joseph J. De La Rosa told state legislators in the Transportation Infrastructure Revenue Subcommittee on Tuesday. “That has been declining, in terms of purchasing power, as the fuel efficiency has gone up.”

De La Rosa is a top administrator for NMDOT, working in a division that specializes in top priority road projects. On Tuesday, De La Rosa spent hours telling a panel of state lawmakers about possible changes to how the state could collect money for future roadwork.

A solution some states use is to charge drivers “road usage fees.” Unlike tolls, which are fees to use certain stretches or road, usage fees charge by the distance driven. Tuesday, state legislators in the Transportation Infrastructure Revenue Subcommittee discussed how usage fees could work in New Mexico.

Fees could be used as “an eventual replacement for the gas tax,” De La Rosa said. It could also “address inequities in how drivers are contributing to the use of the transportation network.”

Basically, drivers who drive older, less fuel-efficient vehicles end up paying more given the existing gas tax, because they have vehicles that use more gas. Meanwhile, hybrid vehicle drivers pay less, and drivers with fully electric vehicles pay no gas tax under the existing system.

By implementing road usage fees, the state could design a system where people are charged based on how much they drive, not how new their car is. To keep track of the miles, the state could rely on GPS trackers in each car. Or the state could rely on New Mexicans to self-report their mileage. And New Mexico is not the only state considering options. Several other states have already tried pilot programs.

“You’ve got California which is near having a statewide program for all electric vehicles,” De La Rosa said. “We have Colorado, who did a pilot, has completed that pilot, and is not at this time pursuing a RUC [road usage charge] that we’re aware of.”

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Several other states have already begun studying road usage fees. Image from NM Legislative Finance Committee.

But there are challenges to implementing a new system. And some legislators voiced concerns about costs or implementing a new system. So why not just raise the existing gas tax? According to De La Rosa, the hike would have to be unreasonably large.

“You would have to increase it so exponentially [and] so quickly, to kind of get to where we need to be, that it just isn’t going to be palatable,” he says. And by simply raising the tax, electric vehicle drivers would still get to enjoy the roads without paying their share.

To be clear, nothing is set in stone yet. There aren’t yet plans to start charging electric vehicle drivers per-mile. This week’s presentation to lawmakers was aimed at sharing information, or bringing the future deciders “up to speed.”

“The DOT isn’t proposing anything,” De La Rosa said. “We’re not here saying, ‘Let’s let’s do this.'” Rather, the idea is to look at New Mexico’s options for paying for roads as more and more vehicles move away from gas.