HONOLULU -- A new study performed by University of Hawaii students and their engineering professor finds alternatives to rail transit will be much cheaper and way more effective in cutting down on traffic travel time.

The city is already moving toward building a steel-on-steel rail transit system, which will cost more than $4 billion.

One of the ideas studied is building underpasses at four busy Oahu intersections such as Pali Highway and Vineyard Boulevard.

The study found that constructing new underpasses, elevated toll lanes and a ferry system would cost less money and be more effective.

The UH students spent more than 1,000 hours studying traffic problems and solutions on Oahu, building computer simulations.

UH engineering professor Panos Prevedouros, a frequent rail transit critic, led 16 students.

"Our study is not to twist anybody's arm. Our study serves the community to show that there are viable alternatives that should be looked at in detail," Prevedouros said.

The study looked at four major alternatives. First: building elevated toll lanes along the freeway and charging motorists about $3 to use them.

"It means the H-1, H-2 (freeways) merge to Iwilei in 10 minutes, in the middle of rush hour," he said. "It's congestion insurance. You pay your 3 bucks, you are guaranteed a free-flow trip to downtown."

Second, a bus rapid transit system that runs up and down King and Beretania streets.

The third proposal was underpasses to take traffic under four busy intersections such as Pali Highway and Vineyard Boulevard and Punchbowl and Vineyard boulevards.

The fourth idea is car ferries cutting across Pearl Harbor from Ewa to the airport or Mapunapuna area.

The study found the total cost of these four alternatives is about $2 billion. The ideas would result in a 40 to 50 percent savings in travel time on the roads.

Compare that to the city's rail transit plan, which the city's studies have found will improve travel time by 6 percent and cost much more, between $4 billion and $5 billion.

"Our proposal is heads and shoulders better, because, we are dealing with 100 percent American technology that can be locally built 100 percent. We have a sufficient number of contractors that can build it," Prevedouros said.

Prevedouros said operation and maintenance costs of underpasses, high-occupancy toll lanes and the like are much cheaper than the money it will take to operate rail transit.