Traffic Q&A: Travel-time signs not cheapest way, but still provide valuable data

Staff writerNovember 11, 2013 

Question: My thought when reading last week’s question about the lack of travel-time signs between Tacoma and Seattle is: Why bother?

I can get travel times on my phone that are more accurate and use exact starting and ending points instead of just “Tacoma” and “Seattle.”

Better questions might have been: How do these new mobile apps work, and why doesn’t WSDOT get with the program?

Those highway signs can’t be cheap. — Jared, Tacoma

Answer: You are correct. “Big data” systems that use crowd-sourced traffic data can be more accurate than the road sensors WSDOT uses.

That’s because crowd-sourced data — gathered from in-vehicle navigation systems, mobile phones, and fleet vehicles such as delivery trucks and taxis — uses many more data points than road sensors. Additionally, the cost to maintain the sensors is expensive and the cost to maintain crowd-sourced information is much cheaper.

WSDOT has worked on occasion with a Kirkland-based traffic information company, INRIX, to augment its data, and according to WSDOT spokeswoman Claudia Bingham Baker, the department has begun to emphasize Web-based presentations.

Jamie Holter, an INRIX traffic analyst who formerly worked for WSDOT, is a big fan of crowd-sourced traffic data. But she says, “I don’t think it’s really fair to question the value of all travel-time signs, because not everyone has access to mobile apps or in-vehicle navigation systems at this time or in the near future.”

“It’s still valuable data,” Holter added, “and the state is smart about locating the travel-time signs at key decision points.”

Rob Carson: 253-597-8693

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