SALEM, Ore. (Feb. 5, 2015) — The use of studded tires in Oregon is declining and should continue to drop, according to a new study performed for the Oregon Department of Transportation and the Federal Highway Administration.
Studded tires appeared on 4 percent of the registered vehicles in Oregon in the winter of 2013-14, the report said. This compares with 16 percent of registered vehicles in 1995, the last time Oregon commissioned a study of studded tire use.
Whereas many Oregon vehicles had studded tires on only the drive axle in 1995, nearly every car or truck with studded tires in the state had them on both axles in 2013-14, according to the report. Even so, this created an effective studded tire use rate of only about half of what it was in 1995, it said.
Although studded tires improve braking, traction and cornering on icy surfaces, the report stated that those improvements can be offset by a slight decrease in driving speed.
“Research shows that non-studded winter tires perform as well or better than studded tires in almost all winter driving conditions,” it said. “Considering studded tire alternatives and popularity of all-wheel- and four-wheel- drive vehicles, studded tire use and the resulting damage of the pavements is expected to continue to decline.”
The report's authors estimated that total pavement damage in Oregon cost $27 million in 2012. They estimated effective pavement damage — damage sufficient to reduce useful pavement life — at $8.5 million.
The latter estimate was the average of three different cost scenarios with a low of $3.8 million and a high of $11.3 million, they said.
Through 2022, the report said, total expenditures for repairing studded tire damage on roadways should be around $44.2 million, averaging three scenarios going as low as $26.8 million and as high as $64.4 million.
These estimates are for Oregon's state highway system alone, and do not include county or city roads, the report's authors said.
Studded tires are allowed in Oregon between Nov. 1 and March 31.