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Ask the Traffic Team

Welcome to "Ask the Traffic Team," a Web page created to answer your everyday questions about statewide traffic issues. The links to the left allow you to view questions about specific areas of the state, as well as search our archive of frequently asked questions. 

If you'd like to submit a question to the Traffic Team, simply e-mail us and provide as much detail as possible. You can typically expect a response with a week.

Specific areas:

I-90 flammable cargo
Charles from Seattle thought flammable material was prohibited on I-90 between Seattle and Mercer Island, but he recently saw several tanker trucks on the highway. Is this allowed?

SR 531 ramp
Mike from Stanwood worries about the sharp curve in the on-ramp from eastbound 172nd St (SR 531) to southbound I-5 in Arlington. The sharp bend makes it hard to see traffic coming down the loop ramp from westbound SR 531. Can WSDOT install a merge sign?

Mukilteo ferry signal
Chris from Mukilteo likes the new signal at the Mukilteo ferry dock, but wonders why the signal faces ferry traffic only. It’s hard for turning drivers to anticipate when traffic will start moving off the ferry again.


Q: Is flammable cargo allowed on I-90?
Flammable cargo is allowed on I-90 most of the time. However, we do restrict flammable cargo whenever we have to take the fire suppression system inside the tunnels out of service for routine maintenance. We inspect the fire suppression system several times a year. It’s during this routine maintenance that we post the flammable cargo restriction on our electronic messaging signs so drivers with flammable cargo know that a restriction is in place and can take an alternate route across the lake. Cargo restrictions are announced on this page:  

You can also get information about flammable restrictions from our I-90 construction page: Even though we call it the construction page, we list I-90 flammable closures there just as soon as we're notified.

Q: Can WSDOT install a merge sign on the SR 531 ramps to southbound I-5?
We understand that the new on-ramps from SR 531 to I-5 at Smokey Point can take some getting used to, especially if drivers don’t use them on a regular basis. The loop ramp from westbound SR 531 crosses under SR 531 and merges with the eastbound SR 531 ramp prior to merging onto I-5. Once the eastbound and westbound on-ramps merge together, drivers have extra distance to speed up before merging onto I-5. The angle and height of the eastbound ramp as it approaches the merge area with the westbound ramp gives drivers ample opportunity to see and anticipate traffic coming from the left on the westbound ramp.

Even though state law doesn’t specifically state which driver has the right of way at a freeway merge, merging is a shared responsibility between drivers. Drivers on the westbound on-ramp need to be considerate of drivers entering from the eastbound on-ramp who are entitled to join the traffic flow. To draw attention to merging traffic, each ramp has a yellow merge warning sign installed to help remind drivers they may need to adjust speed and make room for merging traffic ahead. Eastbound on-ramp drivers have their own role to play, and should adjust their speed to match that of drivers on the westbound ramp, then use their turn signal, and merge into the best available gap in traffic.
*This question and answer came to us from Bill Sheets and his Street Smarts column in the Everett Herald.

Q: It's hard to see when the signal for ferry traffic in Mukilteo will turn green again. Can WSDOT fix that?
It’s nice to hear that the recent improvements we made to the Mukilteo Ferry Dock have made a difference for drivers and pedestrians. However, we have no plans to change the current setup of the signal. The “new” signal isn’t actually brand-new – instead, it’s just been moved to a new location at the intersection. Before our project, the signal was located in the middle of the transfer span. Moving the signal allowed us to decrease the time between light cycles and add a pedestrian crossing during the ferry unloading process – all without delaying the ferry unloading time.

Moving the signal to the intersection allows drivers off-loading from the ferry to see stopped vehicles at other legs of the intersection more easily, and that, in turn, allows drivers and pedestrians to make better decisions about when to cross the street or enter into traffic.
*This question and answer came to us from Bill Sheets and his Street Smarts column in the Everett Herald.
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