State Route 520 bridge tolls alter Interstate 90 commutes
January 10, 2012
State transportation planners said local traffic patterns shifted as motorists adjusted to tolls on the state Route 520 bridge.
Though motorists on the bridge across Lake Washington between Seattle and Medina experience shorter commutes, drivers elsewhere noticed changes in traffic congestion and longer travel times.
The morning commute on Interstate 90, for instance, started sooner, almost 30 minutes earlier than normal.
Data from the Jan. 4 morning commute indicates state Route 520 bridge experienced 30 percent less eastbound traffic and 35 percent less westbound traffic during the 7-9 a.m. peak morning commute compared to normal. On the other bridge across Lake Washington, however, the peak commute started 30 minutes earlier than historical averages and commuters experienced travel times near the high end of the normal range.
Planners said as motorists use I-90 as the alternative to state Route 520, traffic volumes increased slightly and travel times increased up to five minutes more than normal. The state recorded the typical westbound travel time from 6-8 a.m. at 11-20 minutes.
Eastbound I-90 from Seattle to Bellevue traffic volumes increased slightly, but travel times remained normal. The typical eastbound travel time from 6-8 a.m. is 11-20 minutes.
“Every day, drivers are making choices whether to avoid the toll or avoid congestion,” Department of Transportation Toll Director Craig Stone said in a statement. “We are seeing signs that we are edging toward that new normal for the morning commute and are closely monitoring where and when drivers are traveling to see what emerges.”
Tolling on state Route 520 is expected to raise $1 billion overall for the $4.65 billion replacement bridge project. The target date to open the replacement bridge to traffic is December 2014.
The existing state Route 520 floating bridge opened to traffic in 1963 and is vulnerable to sinking during a severe storm after weathering decades of wind and waves.