The neighbors reluctantly accept traffic winding past their houses as the price of living near downtown and the drivers expect to wait in long strings of brake lights on their path into and out of town.

Now a tunnel proposed as a solution to ease the traffic - and the tension - could actually widen the rift between the two sides.

Davis County legislator Sheryl Allen calls the idea "fabulous." But Marmalade Hill homeowner Bonnie Mangold is skeptical.

University of Utah civil engineering students propose a 3,000-foot, $20 million underground commuter roadway following the route of Main Street and Columbus Street, the streets just west of the State Capitol, between 300 North and 500 North. The students will present their plans at a public meeting this morning.

For decades, hostility - and traffic - has been building. Utah's Capitol was built in the early 20th century on a sparsely inhabited bluff above Salt Lake City. Neighborhoods grew up around the building. And workers from bedroom communities at points north followed, chugging their way through the narrow neighborhood streets in their cars. An estimated 18,000 to 20,000 vehicles travel the road daily.

University Civil Engineering Department chairman Larry Reaveley figures the tunnel is the best way to make up for the organic - but not auto-friendly - development of the neighborhood around the Capitol. Reaveley, a member of the board that oversees the Capitol complex, charged his students with designing the tunnel as a senior project this semester.

"This is the only thing I've seen that attempts to suggest a possible solution," Reaveley says. "It goes a long way to trying to resolve problems that have been building for half a century."

But some are more cautious - about the price tag and the unintended consequences of easing the commute on crowded streets west of the Capitol.

Commuters "fail to realize they are going through an historic residential area and the road is two lanes wide," says Mangold. "We don't want to encourage more traffic. We're trying to get traffic to go to other routes."

The project isn't Boston's Big Dig. Still, the cost of digging out the street and covering it back over is daunting to Salt Lake City Councilman Eric Jergensen. He says the tunnel would be in line behind other projects competing for scarce city dollars - including a reconfiguration of the Grant Tower curve and other routine street projects. Besides, making it easier for commuters to pass through the neighborhoods would undermine city efforts to slow down and divert the drivers to 300 and 400 West and North Temple and South Temple.

"The streets just were never designed to handle that traffic," Jergensen says. "There are other ways to do this. I don't know if building a tunnel is the right solution."

But Allen, the Republican lawmaker from Bountiful, says Salt Lake City's efforts to choke traffic run counter to its economic development interests. Building a tunnel would do wonders to soothe commuter frustration, she says.

"Whatever the price tag is, it needs to be seriously considered," Allen says. "Everything Salt Lake does is an impediment to us getting into Salt Lake City. You can't keep shutting the door when there is not a mass transit alternative."