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. Studded tires were introduced in the United States in the early 1960s (1). Since that time, the public has come to associate improved traction and driving safety in winter with the use of studded tires. Numerous references have also indicated that studded-tire use increases the rate of pavement wear for both asphalt and portland cement concrete (PCC) surfaces. The use of studded tires and the extent of pavement rutting attributable to them have been topics of spirited debate in the northern snow states, specifically whether user benefits are worth highway agency costs to repair damage caused by studded tires. For example the Alaska Department of Transportation and Public Facilities (DOT&PF) estimates highway damage from studded-tire use in Alaska to be $5 million annually (D. Esch, unpublished data). The Oregon Department of Transportation (ODOT) recently published a preliminary report (2) that estimates studded-tire damage for 1993 to be $24 million on the state highway system and $18 million on city and county roads, for a total of $42 million in damage statewide. This new ODOT estimate increased by an order of magnitude previous estimates of pavement damage from studded tires. Clearly, there is renewed interest in Oregon to accurately determine the rate of pavement wear from studded tires and whether perceived safety benefits outweigh annual highway damage. BACKGROUND Studded tires were first authorized in Oregon in 1967 (3). Within a few years, excessive pavement wear became apparent. This led to a 64 TRANSPORTATION RESEA...

Framework for Selecting Effective Preventive Maintenance Treatments for Flexible Pavements

“…One type of distress that can be addressed by preventive maintenance is wheel track ruts due to densification of the mix or to studded tire abrasion (17). Microsurfacings and thin hot-mix overlays are normally used to correct this type of distress.…”