I-90 evening commute may bring baseball flashbacks

On the first post-holiday night of the commute with tolls on the state Route 520 Bridge, traffic on Interstate 90 is expected to back up.

Though the morning commute went smoothly, Jim Bak with traffic tracking company INRIX said backups are expected Tuesday night.

• SPECIAL SECTION: 520 Bridge Tolling

“Even though volumes are increasing, they haven’t maximized enough on the road network to really cause any backups this morning,” Bak said.  “But where we do expect to see backups is on the evening commute.”

Bak said if people start to move in a major direction to take I-90 instead of SR-520, traffic might be similar to conditions in 2001, when the Mariners had a 116-win season and there was a 7:30 p.m. night game with people heading into Seattle.

“In a worse-case scenario in the evening commute, that’s what it might feel like for folks trying to travel downtown for a 7:30 p.m. Mariners game a couple years back,” said Bak.

State Route 520 will likely be lighter than usual. 

"It will likely be the best commute in years," Bak said, referring to 520.

 Tuesday morning's commute was lighter than expected for both 520 and I-90, according to INRIX. Data sensors that showed travel speeds on I-90 were normal, although with heavier traffic volumes. By about 7:30 a.m., I-90 data sensors put speeds over the bridge at 10 to 20 mph slower than usual, based on historical speeds.

WSDOT Secretary Paula Hammond said the overall commute wouldn't be truly tested until several months down the road, by which time commuter habits will be more firmly established. KIRO 7's Michelle Millman asked  Hammond what it would mean for tolling and revenue if those speeds and traffic volumes held steady and stayed in place six months from now.

"If you were noticing, when we sold our bonds and as we looked at our traffic control projections, the most conservative numbers that were assumed, assumed about a 40- to 45-percent reduction in traffic, which is why we predicted that 520 would be wide open in the commutes this morning," she said.

WSDOT officials said that between 7 and 9 a.m. Tuesday, they saw a 60- to 70-percent drop in vehicles on the 520 Bridge, compared to a normal work day.

Bak said that later in the week, people may leave for work earlier than usual to beat the traffic, making for an earlier rush hour.

Traffic may also get worse in coming days and week, he said.  People may have stayed home from work Tuesday to see how traffic volumes looked so they can better plan their own commute.