LETS GET REAL. The highway lobby still expects to build its way out of congestion.

A plan to widen part of Interstate 10 in metropolitan Phoenix from 14 lanes to 24 is the USA's latest giant superhighway proposal designed to ease the kind of gridlock that some planners say could stunt economic growth.

For a 2-mile stretch between U.S. 60 in Tempe and State Route 143, the interstate would have six-general purpose lanes, two carpool lanes and four lanes for local traffic in each direction. Work on the first phase, which planners expect to cost about $550 million, could begin by 2011.

Two miles of widened road, which will only generate greater congestion at the end of the widened section, and when the widening is completed, at best it will shorten the duration of the congested period, without shortening anybody's travel times (yes, I CAN document that, and I will have an extended post on this point this weekend) and at an expenditure approximately 80% of Amtrak's annual budget. Is it really in the national interest for all of us to dig down to build a little bit of extra road so that the good people of Phoenix, who are already living off of our largesse in the form of the Salt River and Colorado Basin water projects, can build even more Wisconsin-style golf courses in a desert?

The superwide highway in Phoenix will cut dangerous weaving at interchanges, reduce freeway congestion and add capacity for a booming population, planners say.

"The Phoenix metro area is growing like crazy," says Eric Anderson, transportation director for the Maricopa Association of Governments, the regional planning agency that coordinates freeway construction projects. "We're adding about 125,000 people a year, and we have a population approaching 4 million."

The section of I-10 proposed for widening now carries about 294,000 vehicles a day. That will jump to a projected 450,000 by 2025, says Arizona Department of Transportation spokesman Doug Nintzel.

Do the math: although the capacity appears to expand more than proportionately to the traffic, the perception of a shorter travel time will induce people to leave later for their destinations. In addition, there is no reason to believe that the current projections of traffic for the out-years will be any more accurate than the late 1950s projections of Interstate System use.

"These are really very big bottleneck-improvement projects," says David Schrank, a researcher at the Texas Transportation Institute. "When these highways were designed and built decades ago, the traffic that's there today could hardly be foreseen. A lot of these interstates designed and built in the '50s, '60s and '70s are needing a modernization. … That's happening nationwide."

It's true that the existing Interstate system is clapped out, but is an in-kind upgrade the most efficient use of public funds?