Safety, education, road conditions, and awareness all factor into the studded tire discussion and have to be considered as decisions are made. The following bullets attempt to highlight the key points that surfaced as WSDOT evaluated the studded tire issue:
- Rutting damage caused by studded tires is limited to state routes, primarily on the interstates. This is due to the higher speeds and volumes.
- Concrete: 100% of rutting damage is related to stud use (roughness, noise)
- Asphalt: Approximately 60% of the rutting damage is related to stud use.
- Rutting leads to ponding, hydroplaning, excess roads spray, and “auto-pilot” problems. All are safety issues, but are somewhat difficult to quantify.
- Research indicates that stopping distances for studded tires are greater than the stopping distance for all other tires on wet or dry pavement.
- Modern stud alternative tires (such as the Toyo “Observe” or the Bridgestone “Blizzak”) are superior to studded tires in all snow conditions except for clear ice near freezing temperatures. Some are now better than studded tires in all conditions.
- WSDOT has an aggressive snow and ice removal program. WSDOT estimates that conditions where studded tires would offer an advantage (clear ice near freezing temperatures) occur 1% or less of the time on state routes. The percentage of time will continue to decrease as WSDOT’s anti-icing expands.
- There are approximately 54,000 miles of city/county roads compared to about 7,000 miles of state routes. The perception that studded tires allow the driver to feel safer is probably valid due to a much higher likelihood that snow and ice conditions exist on city/county streets during and after a storm event to a much greater degree than on adjacent state routes.
- According to a recent survey, the public is unaware of the safety issues as well as the alternatives to studded tires that exist. Additionally, the safety issues did not appear to resonate with people.
- The survey indicated that most people would not be willing not pay a fee, even as low as $5, on studded tires. The survey also indicated that a ban on studded tires would not be a significant concern to a majority of drivers.
- WSDOT worked collaboratively with the tire industry over the past several months. The industry has taken a major shift in perspective – their marketing and education are now focused on alternatives to studded tires for winter driving.