Designed for a few roadsters and woodies some 60 years ago, U.S. 189 through Provo Canyon can't safely handle the steady stream of Lasers, Saturns and other new-age automobiles that currently traverse the meandering highway.
The accident rate on the scenic byway paralleling the Provo River is 40 percent to 80 percent higher than on similar two-lane roads in the state. Rapid growth and increasing traffic volumes have exceeded the capacity of the highway connecting Provo/Orem and Heber City. Inconsistent design speeds, impaired sight lines and narrow shoulder widths contribute to the accident rate."It's probably the most dangerous road in the state," said Randy Park, Utah Department of Transportation project manager.
The stretch from the canyon mouth to Upper Falls was widened from two to four lanes three years ago. Reconstruction of a two-mile section from Upper Falls to Wildwood, just beyond the Sundance turnoff at U-92, including two tunnels, is at least a year away.
And for the next 12 months, Centennial Engineering Inc. will develop plans to widen five miles of highway from Wildwood to Deer Creek State Park. Price tag: $50 million.
The preferred plan, according to a 1989 Supplemental Environmental Impact Statement, calls for a four-lane highway and five bridges crossing the river and a sliver of Deer Creek Reservoir. The entire stretch would accommodate 50 mph traffic and eliminate the 30 mph curve at Horseshoe Bend and bypass the dam.
"This is going to be a real challenge," said Mike Stroud, a Centennial engineer. Engineers have drawn several variations to the plan. The project is divided into four segments.
- Wildwood to Horseshoe Bend. Narrow canyon walls leave designers few options. Widening the road would leave little room for access to the river and could necessitate high cut slopes in the canyon walls.
One option is to move the road away from the river and into the hillside, but that would require even higher cuts into the mountain.
A split alignment in which traffic lanes up and down the canyon would be built at different elevations, would reduce the cut slopes and amount of earth to remove, said Mike Robertson, a Centennial engineer.
- Horseshoe Bend to Heber Creeper Bridge. "That's probably our biggest technical challenge," Stroud said.
Hoover Slide, a massive earth movement area near Canyon Meadows, would not provide stable abutments for the two bridges to bypass Horseshoe Bend proposed in the 1989 plan.
"It just won't be able to tolerate that kind of movement over a few years," said Lee Abramson, a geotechnical engineer. "We're trying to avoid putting any structures in there.
One option has the highway running above the bend, just below the subdivided portion of Canyon Meadows. Residents in the area favor anything but that option.
Another proposal flattens out Horseshoe Bend and requires large earth cuts and a retaining wall.
"All of those have some quality that we're not real fond of," Robertson said.
- Heber Creeper Bridge to Deer Creek Reservoir. Three proposed bridges make the section the most expensive of the four. Engineers are looking for ways to eliminate using three spans to cross the Heber railroad tracks, the river and a slice of the reservoir.
One option makes one bridge out of two bridges west of the reservoir. Another replaces the bridge across the water with a split, banked-curve alignment.
Rock falls and avalanches are common in the area.
- Deer Creek Reservoir to Deer Creek State Park. The proposed road closely follows the existing highway, prompting no significant changes. Deer fencing will be installed to protect deer and elk winter range.
Reconstruction could begin as early as spring of 1996, Robertson said.
Centennial Engineering Inc. will accept written public comment about the proposed reconstruction of U.S. 189 in Provo Canyon until May 13. Comments may be sent to Michael Stroud, Centennial Engineering Inc., 310 E. 4500 South, Suite 200, Salt Lake City, UT 84107.