Utah Department of Transportation officials told state lawmakers Wednesday that existing and future carpool lanes on I-15 could be turned into HOT or "high-occupancy toll" lanes.

That conversion, which could take place no earlier than late 2006, would allow individual motorists to buy permission to use the HOV — high-occupancy vehicle — lanes without carrying passengers.

"What we're doing here is consistent with . . . our strategic goals of trying to make the (state highway) system work better," UDOT deputy director Carlos Braceras told the Transportation Interim Committee.

"Even under the HOT lane scenario, the goal is still to provide the travel-time advantage for people who choose to carpool. But we want to be able to move more people, not necessarily cars."

Preliminary results from UDOT's ongoing study of "managed lanes" show the existing carpool lanes — from 400 South to Point of the Mountain on I-15 — carry about 650 to 800 cars during peak hours. The general-purpose lanes, meanwhile, carry about 2,000 cars apiece during rush hours.

A carpool lane does, however, carry more people than a general-purpose lane during peak hours, Braceras said. But there is "available capacity" to put some single-occupant vehicles in the carpool lane without slowing traffic in that lane, he said. If the HOV lanes do become HOT lanes, however, they still could be used free by any vehicle with two or more passengers.

"The way it's been used around the country, it's completely automated and the price changes based on how much people are using the carpool lanes," Braceras said. "They try to use the price to make sure they don't take down the travel time for the carpool lanes."

UDOT has yet to determine how much it might cost for a single-occupant vehicle to use the I-15 HOV lanes. But spokesman Tom Hudachko said the price would have to be low enough for people to choose that option, yet high enough so that not everyone would. For example, $50 a month would be too expensive and $5 a month would not be enough, he said.

Hudachko added that if the HOT lane idea is approved by the Utah Transportation Commission, Utah's HOT lanes likely would not be automated at first. Probably, a sticker would be sold at a to-be-determined monthly rate.

Braceras stressed the managed lanes study "is not a decision document" and said the public will have input on any proposal to introduce HOT lanes or other techniques like reversible lanes and toll roads. The ultimate decision will be up to the Transportation Commission.

UDOT, however, is currently conducting a HOT lanes feasibility study and is considering recommending to the commission a pilot program that would convert all I-15 carpool lanes into HOT lanes by late 2006 or shortly thereafter. That is when UDOT expects to finish adding two carpool lanes — one in each direction — in Utah County, between Alpine and University Parkway in Provo.