Seattle transportation officials are looking into what went wrong after cars started spinning out of control on a de-iced West Seattle Bridge on Monday.
Three minor car crashes in the eastbound lanes shut down the bridge for several hours. Police blamed the de-icer used on the bridge, but the formula, which the city has been using for three years now, didn’t seem to have caused any problems in the westbound lanes on the same bridge.
Still, the Seattle Department of Transportation is checking to make sure the de-icer had not been contaminated, said spokesman Rick Sheridan.
"We’re talking with our manufacturer to ensure that the composition of material was as it should have been," he said.
Sheridan added officials are also working to determine whether daytime use of the de-icer triggered the problem.
On Monday afternoon, with a forecast predicting freezing temperatures in the evening, SDOT de-iced several roads, including the West Seattle highway. The de-icer is typically used during the evening when temperatures are colder and traffic is lighter, Sheridan said.
Another possibility might be the elevation, said Sheridan. While surface roads are sometimes warmer than the temperature of the air, elevated arterials typically freeze the fastest.
SDOT relies on various weather forecasting tools to plan its snow response.
