Is it the answer to Honolulu's traffic problem or just HOT air?

Supporters of HOT lanes, or high occupancy tollways, feel they've gotten short shrift as the debate over mass transit has played out in the state Legislature and City Council this year.

But they say the idea makes so much sense that eventually residents and politicians alike will come around to their way of thinking. They worry, however, that the government will throw away billions of dollars on an unpopular rail line before the change comes about.

"Rail is a sure loser. I'll stake my entire reputation on that," says Panos Prevedouros, an engineering professor at the University of Hawai'i-Manoa. "But there's a parochial mindset here that we just have to have rail, so that's the way it's going."

Prevedouros, businessman Cliff Slater and others say that a new reversible, elevated, variable-priced tollway offers a cheaper, more efficient and popular way to deal with O'ahu's growing roadway congestion.

Despite their pleas, almost all the talk about mass transit this year has focused on rail.

And while city leaders say officially that HOT lanes will be considered in the coming months as part of the formal Locally Preferred Alternative study process to determine the best system for Honolulu, the odds for road options seem long.

The state and city legislation authorizing a general excise tax increase to pay for a transit project specifically says the tax "shall not be used to build or repair public roads or highways," and critics of the LPA study process say it is heavily weighted in favor of rail.

"With the ill-advised passage of this large tax increase, there would be no turning back — the die would be cast for rail," Hawai'i Automobile Dealers Association representative David Rolf warned City Council members on the day earlier this month they voted to approve the tax increase for transit.

That's unfortunate given a small but growing trend toward HOT lanes around the world, proponents say.

HOT projects are highway lanes that give preference to buses, car poolers and drivers of single-occupant vehicles who are willing to pay an ever-changing premium price for the right to travel at faster speeds than congested regular lanes.

In the I-15 freeway in San Diego, for instance, a computerized system raises or lowers the entry toll on a former HOV lane every six minutes between 75 cents and $4 depending on how many drivers are on the road. The tolls are collected by radio transmitters overhead that read a transponder mounted on the car and automatically deduct the fee from a driver's prepaid account. All the tolls collected help pay for repairs on the I-15 roadway and an express bus service in the area.

Part of the skepticism comes from the fact that there are only four in operation in the United States, although dozens of others are being considered and implemented. None of the existing ones uses a newly constructed road, as supporters propose in Honolulu.

In San Diego, which became the first place to have a HOT lane in 1999, studies have shown that the eight-mile tollway serves about 23,000 motorists, giving them a median time savings of between two and seven minutes during the morning rush hour. In Denver, officials are estimating that a longer HOT lane will offer travel savings of between five and 17 minutes.

On average, 79 percent of the traffic on San Diego's tollway is from buses or car pools; 21 percent is from toll-paying customers, according to the Federal Highway Administration. While tolls in San Diego cover all the operational costs of a HOT lane, studies in other places estimate tolls will pay from 22 percent to 60 percent of operational and capital costs for the projects.

"The object of the toll is to manage the traffic so that the HOT lanes' traffic always flows freely. Higher tolls discourage drivers from using the HOT lanes; lower tolls, on the other hand, encourage more drivers to use them," according to The Alliance for Traffic Improvement, a Hawai'i group pushing for alternatives to rail.

"The critical thing in transportation is pricing and out-of-pocket costs," Prevedouros said. "This makes you think every time you leave the house: Is it worth it to me to pay a little extra to arrive somewhere quickly?"

Critics say building HOT lanes will encourage urban sprawl, increase air pollution, and ultimately cause more congestion. They say rail provides a true alternative for those who use it.

HOT lane supporters, though, think most drivers will be unwilling to trade their cars for a system that will use buses to feed people into and out of one rail line running down the leeward spine of O'ahu.

Given the choice, commuters are certain to pick staying in their cars, said Prevedouros, who just returned from a sabbatical in Athens, Greece.

"For the Olympics there, they built both a tollway and a new urban railway from the airport to town along the same line. Now, the railroad is empty — the average occupancy is just 16 passengers — but the tollway is such a success that they expect to pay off the costs seven years ahead of schedule," he said.

In Honolulu, Slater's ATI group has proposed building elevated HOT lanes from the H-1/H-2 freeway merge in the Waikele area to Pier 16 on Nimitz Highway. They say the project would cost less than $1 billion, almost two-thirds less than the early $2.7 billion estimates to build a rail line from Kapolei to downtown Honolulu. The project could pull an estimated 4,000 vehicles an hour off the existing freeways, leaving more space for other drivers, they say.

Despite legislative constraints and a continuing preference for rail, city officials say the HOT lane alternative will be given fair consideration as the latest mass transit project moves forward.

City spokesman Bill Brennan said one option is to define HOT lanes as a mass transit project because they give preferences to buses.

"We don't really think they're the best answer, but that's not to say they will be excluded from consideration," Brennan said. "At this point in the analysis, all the alternatives are going to be discussed and compared against one another."

The state has no plans to convert existing HOV lanes to HOT lanes, Transportation Director Rod Haraga said. Unlike other areas where car pool lanes have proven unpopular, motorists here are happy with the new extended zipper lane for car pools.

However, the state is continuing planning for an elevated two-lane, reversible Nimitz Highway "flyover" from Sand Island to Iwilei. Initial planning for the flyover, which could someday be converted to carry a rail line, is expected to be finished within a year, Haraga said.

Reach Mike Leidemann at mleidemann@honoluluadvertiser.com.