The I-15 reconstruction project is a 17-mile-long chameleon that has 2,000 legs, rarely sleeps and changes its complexion almost daily.

Those daily changes translate into good news for motorists - the project is ahead of schedule.Since the project began 15 months ago, the project has consumed and regurgitated massive quantities of dirt, steel and concrete - along with the patience and tolerance of motorists - at a rapid pace.

If you pass through the heart of it on your daily commute, it is difficult to ignore its ever-changing face.

Sometimes all you see is dirt, perhaps a large pile you swear wasn't there the day before; a new overpass suddenly looms above your sun visor; or a long row of construction equipment is parked conspicuously in the midafternoon sun awaiting maintenance after 20 hours of consecutive use.

You may not see all that's going on, all that's being accomplished by those busy legs, toiling around the clock under top-heavy hard hats, an unforgiving sun and artificial lights. Perhaps you can only focus on those pesky gravel trucks peppering your windshield with unpredictable projectiles.

But I-15 reconstruction is happening at lightning speed, as construction projects go.

Utah Department of Transportation officials say it is the nation's largest road-building contract ever to use an accelerated design-as-you-go construction method. Wasatch Constructors, the consortium of firms that will get $1.325 billion for re-creating 17 miles of the interstate, says it is well ahead of its own ambitious goal to complete the job in July 2001.

So far, crews have moved 12 million metric tons of dirt, enough to fill the Delta Center 16 times. Much of it has been used to build embankments for the new freeway or has been placed on top of the future road surface to squeeze water out of the soil and speed up settlement.

By the end of this second summer of I-15 work, crews will have started building more than 90 of the 144 bridges the new freeway will contain. One, the 2700 South overpass, is already done and opened.

About 1,000 workers are now out on the project, performing the physical work, and Wasatch hopes to increase that number to 1,500 this construction season. That doesn't include the nearly 500 employees who are busy planning and designing the project and the 60 UDOT staffers who oversee the project and communicate with the public. Combined, I-15 reconstruction employees have worked nearly 2 million hours so far.

Many of those workers are driving dirt and gravel trucks, hauling material from sites in North Salt Lake, Point of the Mountain and elsewhere. That truck traffic, however, is on the decline. About 70 percent of the needed fill material already has been brought onto the job site.

All that labor is quickly producing new infrastructure.

"People are actually able to see the freeway taking shape," said Wasatch spokesman Brian Mauldwin. "Things are beginning to make more sense as they look at them because they can see where bridges will go and where the new elevations will be."

The new 600 North overpass and interchange is set to open in September. The segment that spans the railroad tracks east of I-15 is nearly complete; crews are now applying the concrete road surface. Farther west, steel girders are being placed across the freeway, a process that will require more nighttime closures of I-15 in coming weeks.

Wasatch isn't simply replacing the freeway system, it is upgrading and improving it. The new 600 North interchange, for example, will allow southbounders to exit the freeway and head west, a movement the old structure didn't allow.

The 600 North viaduct will be 98 feet wide, 34 feet wider than the old one. It will have 10-foot shoulders, an additional third lane heading east and a protected pedestrian walkway. The finished product will include decorative railings and lighting, partly financed by Salt Lake City.

The viaduct, too, has been moved back a block to touch down at 400 West. Freeway ramps at 400 South, 500 South and 600 South, too, will drop off and collect vehicles farther west than before, opening new land to development.

And the project isn't just confined to I-15. I-80 is being rebuilt east to State and west toward Redwood Road, and U-201 is getting a face lift as far as - and including - the 900 West interchange.

The first sections of new pavement went down this spring on the southern end of the project and more of the 131/2-inch-thick road surface is finding its permanent home daily. The paving machines cover a width of three traffic lanes, about 36 feet, and are capable of paving a quarter-mile distance in one day.

The concrete pavement - there will be no asphalt on the revamped I-15 - is part of a 36-inch road base that includes layers of gravel with varying compositions.

The pavement is designed to last 50 years. The elevated structures - ramps, viaducts and main-line bridges - are being engineered and built to last 75 years.

Work on the three major freeway-to-freeway interchanges is well under way. The most complex and most expensive is the I-15/I-80/U-201 interchange between roughly 2400 and 2100 South. It will include more than a dozen elevated ramps, bridges and connectors.

On the northeast side of the interchange, column supports already are in place for a 13-span bridge that will take motorists from the State Street/I-80 onramp to the I-15 northbound collector.

It's all happening on or ahead of schedule and within the $1.59 billion budget, according to David Downs, UDOT's I-15 project manager. Downs said some Utahns have mistaken legislative deliberations on how to fund I-15 and other statewide road projects as evidence that the I-15 project is above its spending limit.

"There's a general consensus that we're over budget and that's not true," he said. "People just can't believe that this amount of work can be taking place without being over budget."

UDOT chose to use the accelerated construction process, known as design-build, so it could complete the work before the 2002 Winter Games. The decision to use the method on such a large-scale project has drawn significant attention within the road construction industry. Downs and other UDOT officials have given tours and fielded questions from transportation officials across the U.S. and overseas.

Ultimately, however, it is Utahns who will be blessed with, or stuck with, the end product - a modern testament to the human quest for freedom and mobility that is fast materializing.