SALT LAKE CITY — Lawmakers held their collective breath in anticipation of a final vote on a proposed subsidy for energy-efficient vehicles.

HB29, sponsored by Rep. Steve Handy, R-Layton, failed in the House on a 37-38 vote. The bill would have extended tax credits to energy-efficient vehicles.

After an engaged debate and a close vote, House Speaker Greg Hughes, R-Draper, cast the 38th and final vote against the measure Tuesday night, effectively defeating its chances to move forward.

Supporters of the measure touted it as an opportunity to promote an emerging technology.

"We are talking about market transformation here that would make a tremendous difference going forward," Handy said.

Rep. Dixon Pitcher, R-Ogden, an electric car owner himself, said the self-driving capabilities of the vehicle have allowed him to read his legislative bills while going to and from the Capitol.

“You will not go back to a fuel-combustion car again,” Pitcher said.

Rep. Patrice Arent, D-Millcreek, the leader of the Clean Air Caucus, said there would be no "silver bullet" to resolve Utah's clean air concerns, but a number of measures — like the subsidy for energy-efficient vehicles — would improve air quality.

“If the technology is so great, it does not need a subsidy,” countered Rep. Timothy Hawkes, R-Centerville.

Rep. Scott Sandall, R-Tremonton, joined the opposition to the bill, saying the measure offered a nearly $400,000 subsidy for about 300 vehicles.

“And those vehicles are going to be recharged by 70 percent coal. The whole bill does not make sense economically to me,” Sandall said. “I like clean air, I want clean air, but this bill does not get me there in an economically sound way.”

Rep. Mike Schultz, R-Hooper, raised concerns about the cost and suggested that owners of energy-efficient vehicles already enjoy an incentive by not paying the gas taxes that those with other vehicles pay.

Handy said a lack of incentive to those outside the Wasatch Front may have turned some lawmakers away.

"They do not get that air quality on the Wasatch Front affects the whole entire state from an air quality and economic development standpoint," he said.

Handy said he would "sleep on it" and consider whether to try to resurrect the bill at some point.