But city officials are perturbed that Dane County isn't yet signaling a financial commitment to the project.

City engineers are calling their proposal for the new intersection design a "modified jug handle" because it involves elevating half of Junction Road and building an off-ramp in the southwest corner to connect to Mineral Point Road.

The design would be unique in Madison, said Deputy City Engineer Rob Phillips.

"We did not anticipate that this would be an (overpass) at the time this area was developing," Phillips said.

City officials contend the congestion has been driven by the growth of Madison, Middleton, Verona and Fitchburg that wasn't anticipated when the roads were originally built. The county views development in Madison as a major contributor.

Drivers and residents have been complaining about congestion at the Far West Side intersection for more than a decade. City traffic engineers have given the intersection an F rating, for failure, at certain times of the day when drivers often wait two light cycles to turn left.

Commercial development as well as commuters traveling between Middleton and Verona have ballooned traffic counts over the years. And with future development expected in the area, including phase two of the University Research Park at the southwest corner, congestion is expected to get worse unless the intersection is updated.

County Highway M has seen traffic grow from 8,150 vehicles a day in 1990, to 15,150 in 1999, to 21,700 in 2005. By 2030, the number is expected to reach 32,000. The number of vehicles on Mineral Point Road is expected to increase from 40,500 today to 70,000 by 2030.

The proposal would cost $3 million to $5 million to acquire property and $8 million to $11 million for construction, which is expected to begin in 2011. The city has projected the cost to be nearly $18 million over the next five years in its capital improvement plan.

Phillips said federal highway funds would be used to pay for 50 percent of the construction cost. The university has been asked to dedicate $800,000 worth of land to the project and a preliminary estimate of special property-tax assessments in the area is $2 million.

Dane County has participated in the review process, but has not committed any funding to the project in its long-range capital budget. Officials said the county's policy is to wait for a firm financial commitment from the private sector before signaling support.

"Proposals like this one that are largely generated by a pending private development where the developers are the ones benefitting, the consistent county policy is the developer should shoulder some of that cost," said Josh Wescott, spokesman for Dane County Executive Kathleen Falk.

"As far as I'm concerned, that doesn't cut it," said Ald. Paul Skidmore, 9th District, who represents the area for the city and is a member of the Madison Area Transportation Planning Board.

The board, which serves as a regional transportation planning agency, rated the intersection the highest priority among Madison's 2011 and 2012 highway projects.

Skidmore said there are city government officials who are frustrated with the county's position. "I'm concerned that the county is not stepping up to pay their fair share," he said.

Sup. Dianne Hesselbein, who represents the area on the County Board, said the intersection has become severely congested, even dangerous. But she wouldn't say whether the county should contribute to the project.

"I think the county has to take a long, hard look and prioritize what's important to them," Hesselbein said.

Ald. Robbie Webber, 5th District, who also is a member of the transportation planning board, has expressed reservations about building more highway capacity to solve congestion, evoking the comparison to loosening one's belt to lose weight. She praised the proposed design, but called the project a "bad investment."

"It's a ridiculously expensive project, and considering that it's two county highways, I think it's ridiculous that the city of Madison is expected to pay for all of it," Webber said.

Residents are invited to learn more about the proposed design at a public information meeting Thursday.

The design includes elevating the southbound lanes of Junction Road and creating a J-shaped off-ramp (the jug handle). Southbound drivers trying to get to the Beltline would make two right turns. A right turn from Junction Road onto Mineral Point Road would require driving over Mineral Point Road and hanging a right on the jug handle, followed by a left at a new traffic light.

The design includes bus stops, bike paths and ramps, and pedestrian crosswalks on the northbound lanes of Junction Road.

By elevating half the highway, businesses east of Junction Road wouldn't be in the shadow of the overpass. One business, Steve's Liquor on the northwest corner, would have to be removed.

The option also was chosen because it would allow a left turn from Mineral Point Road onto Commerce Drive.