SDOT says human error to blame for West Seattle Bridge de-icing crashes

The Seattle Department of Transportation admits a series of crashes on the West Seattle Bridge happened because a driver applied de-icer at twice the rate it should have been.

Officials made the admission in a briefing Tuesday with the Seattle City Council Transportation Committee.

SDOT road maintenance manager Steve Pratt told the council he ordered the de-icer application in an effort to get ahead of a storm predicted to hit during the afternoon rush hour and Monday Night Football game at CenturyLink Field.

The solution containing Magnesium Chloride is known to make conditions slick if applied at 40 degrees or higher.

“We were trying to be pro-active,” Pratt told the Council. But he admitted it was a judgment call that backfired when temperatures didn’t drop, as forecast, and the driver applied twice as much solution as he should have.

“It was an “unfortunate event,” Pratt said. “A plain and simple error.”

Rather than applying the solution at 15 gallons per lane mile, the dial was set to 30 gallons per lane mile, said SDOT director Peter Hahn. “It’s really not that mysterious. The setting was off and a mistake was made.”

Officials again apologized to all those impacted. Both the driver and his supervisor are to blame, said SDOT communications director Rick Sheridan in an interview with KIRO Radio.

“It is something that obviously we take responsibility for and that we will provide additional training to that operator and supervisor to ensure that it does not happen again.”

Along with additional training, Sheridan said SDOT would try and limit de-icing operations to the late evening hours when traffic is the lightest, or work with the Seattle Police Department to manage traffic and notify drivers if de-icing is determined to be needed during the day.