The brakes on a dump truck failed Friday afternoon as the driver descended Marsac Avenue between Deer Valley and Old Town, the Park City Police Department said, sending the truck rumbling onto Deer Valley Drive before it crashed into an embankment.
It is believed to be among the most dramatic crashes blamed on failing brakes in years along the notoriously steep Marsac Avenue. Safety measures have been built along the road in the intervening time and the authorities have conducted inspections of trucks that drive the route.
The dump truck at 3 p.m. on Friday was hauling two pieces of unspecified heavy equipment on a trailer as it headed downhill on Marsac Avenue, sometimes called the Mine Road for a stretch. Phil Kirk, a police captain, said the driver told the police the dump truck's brakes failed after passing a truck-escape lane on Marsac Avenue.
Rick Ryan, another police captain, said the dump truck passed a row of houses along Marsac Avenue as well as the Marsac Building on the downhill route.
When the dump truck reached the Old Town roundabout, it drove straight through the middle of the landscaped circle instead of curving around on the road, Ryan said. It hit a rock wall in the roundabout and continued down Deer Valley Drive, he said.
"It looked like it came right centered across" the roundabout, Ryan said.
The dump truck then collided with a rock wall on the east side of Deer Valley Drive before coming to a stop on an embankment a little north of the intersection with Aerie Drive. The dump truck ran over several traffic signs, Ryan said.
The driver, a 49-year-old man from Pleasant Grove, was the only person inside. Ryan said the man was not injured. Ryan said it appears the driver purposely steered onto the embankment in an effort to stop the dump truck. He said investigators found a debris field in the road along the roundabout and at the embankment. The dump truck was towed at 6 p.m.
"It could have been real serious, the time of day. We were just fortunate there wasn't traffic in the roundabout," Ryan said.
Ryan said the dump truck was traveling at an estimated 40 mph as it descended Marsac Avenue. The posted speed limit on the residential part of the route is 25 mph. Ryan said the estimated speed at impact was 30 mph.
The accident remains under investigation. Ryan said the driver could be ticketed. The Utah Highway Patrol found the dump truck's brakes were not working properly during an inspection afterward, Ryan said.
The stretch of Marsac Avenue between Deer Valley and Old Town has long challenged dump truck drivers and others as they head downhill. The road, at its steepest point, approaches a percent grade of 15 percent while other sections range up to a 10 percent grade.
There is a long history of accidents blamed on trucks losing their brakes on the road, including a series of them in the summer of 1997. In one of those cases, a truck barreled onto Deer Valley Drive and through the intersections with Bonanza Drive and Park Avenue before running into a knoll near Park City Mountain Resort.
As a requirement of the 1990s approval that allowed the project now known as Empire Pass to be built, the developers in the early part of the last decade built the truck escape lane along Marsac Avenue. It opened in 2001.
Ryan said there has been a "really significant" drop in the number of accidents involving trucks with failed brakes since the truck-escape lane opened. He also attributed the drop to safety inspections of trucks and Police Department awareness efforts.