From the Spokane/Idaho boarder to the top of the hill leading to Cheney, I-90 has grooves deep enough for one’s vehicle to drive in without using the steering wheel.
Studded tires are the leading cause of the ruts etched deep in the I-90 freeway concrete through Spokane. Any vehicle in the grip of the ruts is carried along as though on rails. Once spit out of the rut, the car or truck is sent wobbling, as the driver struggles to gain control.
Although many believe driving in those grooved lanes may worsen the already bad conditions, Al Gilson, the Public Affairs spokesman for the Washington State Dept. of Transportation says only studded tires increase the damage. "Studded tires are like hundreds of nails chipping away at the cement every time they drive on the road," said Gilson.
Spokane’s I-90 was last replaced over 50 years ago, but it only took the grooves 20 years to appear. In 2007 repairs will begin on I-90 from Latah Creek Bridge to Division.
"The estimated road repair will take two construction seasons. One for westbound and one for eastbound," says Gilson. "Although, we have not yet completed the resurfacing estimates for the downtown Spokane sections."
According to the Washington State Department of Transportation website, studded tires do provide some measure of improved stopping ability on untreated icy roads. Typically, Spokane has snowy winters, but after the roads are plowed of snow, regular winter tires are safer than studs.
Research on studded tires, some dating back to the 1970s, consistently shows that vehicles equipped with studded tires require a longer stopping distance on wet or dry pavement than vehicles with standard tires. That is because tire studs reduce full contact between a tire’s rubber compound and the pavement.
A survey conducted by Washington State of Transportation during the winter of 1996-1997 revealed that, on average, 32 percent of the vehicles in Eastern Washington use studded tires. Spokane had the highest stud usage with 56 percent, and the lowest was 6 percent, in Puyallup.
Pavement rehabilitation is estimated at $10 million per year, and most damage is in the form of rutting. Rutting can lead to hydroplaning, reduced visibility, and loss of directional control.
Concrete ruts less but with Spokane’s dry climate, concrete does not appear to be the practical resource for road material because cement tends to absorb water and gain strength, while asphalt sheds water blocking deterioration.
But with the heavy use of studded tires on the Eastern side of the state, concrete is the logical choice because of its durability, according to Gilson.
Concrete lasts longer than asphalt, but concrete is much more expensive and labor intensive. "Concrete is thick and has a cure time, unlike asphalt where you can lay it and drive on it minutes later," Gilson says. "Concrete may be more costly, but asphalt only lasts 12 years with studded tire use."