BAINBRIDGE ISLAND — It’s been nearly one week since work began on the Agate Pass Bridge, to clean the aging structure.

Since then, traffic on the two-lane bridge has been reduced to alternating one-lane traffic from 8:45 a.m. to 3 p.m.

The bridge — relied upon by commuters en route to the Bainbridge Island ferry terminal — has experienced a reduction of 15 percent in traffic volume during the cleaning, according to Claudia Baker with the Washington State Department of Transportation.

Baker said that she does not know why the drop in traffic has occurred, but speculated that it could be a mix of commuters going to other ferry terminals, and people modifying their travel plans for less important trips.

“On a normal day, there are quite a few discretionary trips people take for things, like grocery shopping,” Baker said. “So it is possible that people are taking less of those.”

Traffic delays during the work have ranged between five and 20 minutes. The department has received two complaints from the public about the delays.

While traffic has been “manageable,” according to Baker, the bridge experienced a spike in traffic volume on Feb. 12.

“We saw traffic volumes creeping back up again,” Baker said. “We want to encourage people to try to stay away from the area if they can, for their own benefit.”

So far, crews have removed daily truck loads of mud and debris from the bridge.

“They are bringing out that amount of dirt every day,” Baker said. “It’s all caught in the frame below the bridge deck. There are a lot of I-beams and things that can collect debris. That bridge hasn’t been cleaned since 1991, so it has had a lot of time to build up.”

Cleaning should finish around 2:45 p.m., Feb. 16, but work on the bridge won’t be finished.

“Cleaning is just the first part of what they need to get done,” Baker said. “Then they will start tackling the rust, and start an inspection.”

The bridge is slated to be open to full traffic on Feb. 28.