Numbers don’t lie; drivers pay attention and keep traffic moving

WSDOT contractor crews wrapped up a busy weekend of work on southbound Interstate 5 between Stewart Street and Interstate 90 in downtown Seattle. Crews are repairing 40-year-old concrete which is deteriorating and falling apart. Broken concrete means tough traveling for drivers and freight haulers. We want to keep our economy moving.

This weekend crews replaced 41 broken and concrete panels and reopened lanes four hours ahead of the 5 a.m. Monday, Feb. 16 target.

But the real story is in the numbers and comes from drivers themselves who plugged in, paid attention and took alternate routes this week. The following statistics come from day-to-day comparisons from 2008 to 2009.

By the numbers

  • On Saturday and Sunday, Feb. 14 and 15, nearly 60 percent of the drivers who usually take I-5 and cross I-5 south of Mercer Street did something different. They took SR 99, local streets, I-405 or stayed home. Sixty percent is an extraordinarily large number! That means more than half of you didn’t take I-5. This might be one for the record books at WSDOT.
  • On Saturday, Feb. 14, 8 percent more drivers used the express lanes to get into Seattle than on the same day last year. We have found in the past that the express lanes are the hardest working lanes that too few people use. Only at 10 a.m. did the express lanes take longer to travel than the mainline.
  • On Saturday, Feb. 14, we saw a 23 percent jump in drivers using I-405 as an alternate route to I-5. That is exactly what we wanted. We hoped that drivers traveling through Seattle would take I-405 so drivers traveling to Seattle could use I-5.
  • Back ups on the mainline never reached more than 45 minutes and that was at 4 p.m. on Saturday.
  • The longest back ups Saturday occurred at 1:30 in the express lanes and at 4 p.m. on the mainline.
  • The longest backs up on Sunday occurred at 1:30 in the express lanes and 11 a.m. on mainline.
What else did we see?
  • Nearly two-thirds of drivers did not use I-5 to get to I-90. They crossed the lake on SR 520 or they used I-405 from Lynnwood and avoided the bridges altogether.
  • We also saw a 48 percent jump in drivers who used the I-90 exit from I-5 to get off and then back on I-5 after the work zone. It’s called a collector-distributor ramp. It functions like a long bypass. That helped lower the traffic numbers in that second construction zone near I-90.
  • It was the same story on Sunday.

Drivers listened to the radio and make smart choices. During the carjacking on I-5 Saturday the I-5 mainline was closed for the investigation. Drivers used the express lanes and SR 99 to get around the pinch point and made it to their destinations.

What’s next
We will close northbound I-5 this weekend from Friday, Feb. 20 at 8 p.m. through Monday, Feb. 23 at 5 a.m. just south of the I-90 interchange. We hope drivers will do a great job again this weekend.

Watch this spot for your traffic congestion report card next Monday.

Check the Web for the latest info in case things change: