Highway construction stories sometimes use the term “carmageddon” to describe the impact on motorists. This time the moniker may be for real.

Starting tonight and continuing until July 25, westbound Interstate 90 between Bellevue and the East Channel Bridge will be reduced to one lane as crews replace two huge — and old — expansion joints deep in the roadway near Mercer Island.

The state will need the public’s help. And motorists likely will need a handful of aspirin — or more — to survive the ordeal.

Oh, and in addition to the closure of three lanes of I-90, motorists also will face some ramp closures.

So, how bad is bad?

In 2009, the state closed two lanes westbound on the I-90 floating bridge. That caused backups of seven miles. This time the prediction is that the backups could extend 10 miles.

The solution, the state says, is for 60 percent of motorists to change their plans. Even so, the commute will be ugly. Normal peak travel times through the I-90 closure area range from up to 15 minutes in the morning to 30 minutes in the afternoon. Even if 60 percent of motorists avoid the area, the state still expects travel times to be 45 minutes to an hour in the morning — and longer in the afternoon.

Business can help by allowing or encouraging workers to telecommute or by adjusting work times. If that’s not possible, alternative routes are the next best choice. However, that likely will increase traffic on I-405 northbound and southbound, as well as on the state Route 520 bridge.

The best option is to avoid I-90 altogether.

Staycation, anyone?

– Craig Groshart, Issaquah & Sammamish Reporter