Drivers on Interstate 90 saw the biggest impact on their commute Tuesday from tolling on the State Route 520 bridge.

According to the Washington State Department of Transportation, traffic on I-90 during the morning commute increased by 25 percent. Eastbound I-90 traffic increased by 20 percent and travel times averaged 4 minutes longer. Typical travel times are 10-16 minutes.

“It appears that a good number of people who typically take the 520 bridge across Lake Washington are exploring their alternatives,” WSDOT Secretary Paula Hammond said. “We saw heavier traffic on I-90 and SR 522 than we typically see during morning rush hour, and we are hearing from our transit partners that many commuters took the bus.”

Drivers who chose to pay the tolls on 520 were rewarded with a quick ride. Travel on westbound 520 from Bellevue to Seattle was 5 to 7 minutes faster, according to WSDOT. Traffic volumes dropped by 45 percent from 5 a.m. to 7 a.m. Typical travel times are 15-20 minutes. Volumes edged up a bit in the 7:30 a.m. to 9 a.m. hour after a disabled semi-truck blocked one lane on westbound I-90 on Mercer Island and pushed drivers to 520.

Eastbound SR 520 from Seattle to Bellevue was 5-7 minutes faster. Traffic volumes dropped by 35 percent. Typical travel times are 12 -20 minutes.

Data shows a large majority of morning and evening commuters have the Good to Go pass. During that peak morning commute from 5 to 9 a.m., 85 percent of the drivers have the pass. Nearly 65 percent of all daily drivers who use the bridge have the pass.

Tolling on SR 520 is expected to raise $1 billion overall toward the $4.65 billion SR 520 bridge replacement and HOV program, which builds 12.8 miles of safety and mobility improvements from Interstate 5 in Seattle to SR 202 in Redmond.

The target date to open the new bridge to traffic is December 2014.

The morning commute tends to be less dense as commuters start the day at different times. The evening commute will be the true test.

“This is just the traffic picture for today. We anticipate more fluctuations in the days, weeks and months to come,” Hammond said.