State project adds high-friction pavement layer to roads with higher vehicle crash rates

WASILLA — An Alaska Department of Transportation paving project is about to get some road-tested feedback as Southcentral Alaska marches toward winter — and winter driving.

A contractor recently wrapped up a summer’s worth of highly targeted resurfacing projects at 28 different sites from the Kenai Peninsula to the Valley, aimed at reducing year-round crashes through the use of a high-friction pavement application.

The surfacing material, a blend of high-quality, small rock mixed with an epoxy, is meant to add greater friction than traditional asphalt in areas that have been identified as having a higher rate of vehicle crashes.

Similar in concept to coarse sandpaper or the nonslip edges at a swimming pool, the treatment is meant to add a layer of rough material to the road in specific areas like curves and banked stretches to improve traction in any weather.

In the Valley, the project focused on much of Wasilla-Fishhook Road and the Old Glenn Highway, two areas identified because of their rate of crashes due to skidding, loss of control and other factors, said DOT engineer Anna Bosin, a coordinator for the $6.75 million project initiated in 2013 through the federal Highway Safety Improvement Program. The federal government covered 90 percent of the project cost, with the state contributing 10 percent. Granite Construction was awarded the contract this year, and has since wrapped up the work for the fall.

“We looked at roads with a crash history such as high crash rates or certain types of crashes (single vehicle run off the road, motorcycle,) severe crash history (fatal and major injury crashes,) and locations where there are limited options for other types of engineering treatments,” Bosin wrote in an email, adding that the friction treatment will be left in place for at least five years.

Wasilla-Fishhook, once the Carle Wagon Trail leading to the mines of Hatcher Pass, winds and rolls its way near the Little Susitna River northeast of Wasilla. According to Bosin, during the 2006-2010 study period, Wasilla-Fishhook had four major injury crashes, five minor injury crashes and 17 incidents which resulted in property damage only, like vehicles sliding off the road into the trees. DOT identifies the road as a “major collector,” with an average of 3,620 daily trips between Lakeview and North King Cove drives. That number drops to 1,620 from North King Cove to McCasey Drive. Those numbers were last updated in 2013, according to the state.

Contractors this month also are working to clear trees and brush from the right-of-way along 10 miles of Wasilla-Fishhook, part of separate state safety program, according to DOT spokeswoman Shannon McCarthy.

The project differs from the usual state right-of-way clearing in that it targets for removal only specific trees or groups of trees, McCarthy said.

“The project focuses on areas identified with trees that are obstructions in the ‘clear zone,’ are contributing to shading on the roadways and are interfering with the driver’s ability to see conditions ahead,” McCarthy said.

On the Old Glenn, Bosin said the road had four fatal crashes, one major injury crash, 21 minor injury crashes and 17 that involved property damage. Also identified as a major collector, the Old Glenn averages between 2,000 and 3,500 daily trips.

Other areas included sections of the Seward and Sterling highways on the Kenai as well as a range of streets in Anchorage. The 28 sites had 321 documented crashes with 156 injury crashes, including 38 major injuries and nine fatalities over the study period, according to the state.

“Some locations are only 400 feet in length, while others are close to a mile in length per lane,” Bosin said, adding that some 147,640 square yards were bid for treating all 28 sites.

The treatment can’t be missed — gray asphalt turns into a tan section on the affected roadways. Bosin said the application is more labor-intensive than laying asphalt.

“It is an epoxy-resin type adhesive and a very expensive, hard aggregate that is blown onto the resin,” she said. “The entire application is only a quarter-inch thick. It has to cure. The crew size I saw in action was about a dozen construction staff during installations.”

She said other states have seen success with the program after some winter exposure.

“Vermont, Michigan and Illinois have shown the product stands up well to plowing operations,” she said, “and South Dakota has seen a reduction in winter crashes on their rural application.”

Bosin said program managers will evaluate the sites after three years of crash data is available post-construction. She’s now part of the DOT Statewide Research Development division, which will be monitoring all the sites for rutting, cracking and rideability after some exposure to Southcentral Alaska weather.

“Of course we will monitor the friction value over time to see if it is a cost-effective investment for the department to use other places,” Bosin said. “Values we took this summer show the (treatment) has almost double the friction value of the adjacent pavement.”

Contact reporter Steven Merritt at 352-2269 or steven.merritt@frontiersman.com