Street Smarts reader Pat Lundstrom, of Marysville, wrote in with a question about what — at first glance, anyway — looks like traffic signal overkill at the intersection of 100th Street NE and 51st Avenue NE.

“There are 12 lights at this intersection — three for each direction,” she noted.

In each direction, there is a lane for through traffic and right turns, and a left-turn lane. None of the signals offer a protected left-turn arrow, however. In each direction, there are two signals overhead on the mast — with a sign reminding left turns to yield on green — and a third signal that is lower and off to the side on the pole.

The design and construction of these signals was done by Snohomish County and started before the area was annexed into Marysville.

The formerly crooked intersection was straightened out in 2010, and the new signals were added as part of that work. Snohomish County Public Works followed federal guidelines in the design, county traffic engineer Jim Bloodgood said.

“Other factors taken into consideration for this intersection include the high motorist usage to avoid heavy traffic on 88th Street NE, the Cascade Elementary School location nearby, and a Fred Meyer retail grocery store and cinema in the neighborhood,” Bloodgood said.

The third signal was added in case a large vehicle blocks a following vehicle driver’s view of the overhead signals. “This is an additional safety feature that is installed at other intersections throughout the county, such as 164th or 128th,” he added. The additional signal cost about $500.

The design allows for the addition of a protected left-turn signal, something Marysville plans to do, city spokeswoman Connie Mennie said.

The city is seeking a state grant for the upgrade, estimated at $43,000. “In comparison, the estimated cost of a new signal construction project is between $300,000 and $400,000,” Mennie said.

Construction is expected to start in late summer or fall.

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