Welcome to "Ask the Traffic Team," a Web page created to answer your everyday questions about traffic issues in WSDOT's Northwest Region. You can find common questions sorted by subject in our Frequently Asked Questions archive.
If you'd like to learn more about our Seattle-area traffic camera page, you can check out the Seattle Traffic Questions page.
To submit your question, simply e-mail our Public Affairs office and provide as much detail as possible. You can typically expect a response with a week.
Questions for the weeks of Feb. 3-24, 2012.
North Bend cameras
Jack from North Bend wonders why WSDOT has no cameras between Issaquah and the I-90 summit. Can’t a camera be installed in North Bend?
I-90 ramp meter
Phil from Mercer Island wonders why the ramp meter from West Mercer Way to westbound I-90 cycles so slowly. Often it takes up to 10 seconds for the light to turn green. The Island Crest Way meter, on the other hand, cycles much faster. What’s going on?
SR 9/SR 92 signal
Tom from Lake Stevens wonders when WSDOT will reinstall the right-turn arrow at the SR 92/SR 9 intersection. It was originally removed during construction, but construction seems to be done now.
ANSWERS
Q: Can WSDOT install a camera along I-90 near North Bend?
Unfortunately, we have no plans to add cameras in the vicinity of North Bend at this time. In addition to the pole and camera equipment, new cameras also require power and a link to our traffic operations center in Shoreline – and that can be costly. Typically, our folks here at traffic operations will request that new cameras be added to major construction projects, such as a roadway widening project through that location. These projects are big enough to absorb the costs of new cameras, but there haven’t been any widening projects near North Bend and nothing is planned in the near future.
Q: Why does the West Mercer Way ramp meter work so slowly and the Island Crest Way meter work so quickly?
You have good timing, since we’re in the process of analyzing the meter rates for all ramp meters in our region. Looking at data from the past two months, we found that the Island Crest Way to I-90 ramp meter typically has a longer wait time per vehicle due to the higher ramp volumes than W Mercer Way does. Volumes on the W Mercer Way ramp to I-90 are a lot lower than Island Crest Way. That is why the ramp at Island Crest Way has two metered lanes, whereas W Mercer Way has only one metered lane.
The meter rates aren’t set to a specific time; they fluctuate depending on traffic conditions. Te rates are calculated using a logic system that takes into account real-time ramp volumes, traffic volumes on I-90, and the amount of traffic “downstream” from the ramp. These rates are calculated and updated every 20 seconds. When I-90 is heavily congested, the meter rate would be at the low end so that drivers would have to wait longer to enter the roadway. However, when the ramp volumes are high, the meter will speed up to put vehicles on the freeway at a faster rate to relieve the ramp backups.
Q: When will WSDOT replace the right-turn signal on SR 9 at SR 92?
Tom is correct that we removed that right-turn arrow during construction of the SR 9 widening project in the area. Construction – at least to the casual observer – is done, although we do still have crews out there wrapping some end-of-project work. Since we’re done with all the lane closures, though, we’ll be reinstalling that right-turn arrow. It’s a pretty simple process (crews just have to pull off the old signal head and install a new one), and we hope to get it installed by early January.
*This question and answer came from Bill Sheets and his Street Smarts column in the Everett Herald.
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