7/16/2015
Just over 52 miles of seal coating on Idaho 21, Idaho 75 begins Wednesday (July 22)
STANLEY – Drivers should expect speed reductions and loose gravel along a little more than 52 miles of mountain highway through central Idaho for approximately three weeks as crews complete a roadway seal coat beginning Wednesday (July 22), the Idaho Transportation Department announced. Work is expected to be complete by Aug. 7.
Work will take place on Idaho 21, from the Boise/Custer county line at Banner Creek Summit, to the junction with Idaho 75 in Stanley, a distance of about 25.5 miles. The work continues on Idaho 75 from the Valley Creek bridge in Stanley to the Yankee Fork Ranger Station, about 27 miles in distance.
Through active construction zones, the highway will be reduced to one lane, with a pilot car in operation. Drivers should watch for flaggers and construction vehicles entering or exiting traffic throughout these construction zones.
A 35-mph speed limit will be in effect during the work. Observing posted speed limits and increasing following distance will reduce the risk of windshield damage caused by loose gravel.
A properly applied seal coat can add several years of service to a roadway by preserving the integrity of the asphalt and serving as a barrier to water and cracking. The surface also improves winter safety by adding roughness for traction on snow and ice.
Seal coating begins by applying a layer of liquid asphalt followed by a cover coat of gravel on the roadway surface. The highway is rolled and traffic allowed on to the roadway to help pack the surface before "brooming," or sweeping, to remove excess gravel.
The work is done during the day to allow higher temperatures to bond the asphalt and rock more quickly to the roadway surface, providing a higher-quality finished product.
The Idaho 75 work will skip over the roadway-reconstruction taking place through the Salmon River Narrows area, from about milepost 205 to 207. The $1.85 million project is under contract with Knife River Corporation - Northwest, of Boise.