Use and Effects of Studded Tires on Oregon Pavements

Abstract

The use and effects of studded tires in Oregon are investigated, updating a 1974 report. Studded-tire use was surveyed, rut measurements collected, studded-tire traffic estimated, and pavement wear and damage analyzed. Studded-tire use in Oregon varies geographically. Half of the vehicles equipped with studs use them on all wheels, representing a significant change from 1974 practices. More than 23 percent of vehicles used studded tires in 1994. Studded-tire pavement wear coefficients were calculated and found to be half those reported previously. The coefficients for rigid and flexible pavements are 0.20 mm (0.008 in.) and 0.86 mm (0.034 in.), respectively, per 100,000 studded tire passes. Studded-tire wear will shorten pavement life on high-volume routes in Oregon. Asphalt pavements experiencing average daily traffic (ADT) volumes of 35,000 and 20 percent studded-tire use will reach the threshold rut in 7 years. Portland cement concrete (PCC) pavements experiencing 120,000 ADT and 20 percent studded-tire use will develop the threshold rut depth of 19 mm in 8 years. These estimates substantially reduce Oregon design life expectations for asphalt and PCC pavements. The estimated Oregon studded-tire damage for 1994 is $37 million for the state highway network, with similar damage for municipal and county roads. Alternatives are discussed to reduce the damage caused by studded tires, including a ban on studs, shortened use period, lightweight studs, user fees, and public education initiatives.