Triggering the traffic-light sensor on a motorcycle

Q: There is a light at the intersection of Northeast 37th Way and Sahalee Way Northeast in Sammamish that appears to be tied to a sensor. When you're on Northeast 37th Way turning left onto Sahalee Way Northeast, the light changes green almost immediately. It's terrific! That is, if you're in a car. I ride a motorcycle, and the sensor doesn't detect my presence and the light never turns green until a car arrives behind me, which depending on time of day can be quite a wait. Is there anything that can be done, or is there something I can do to trigger the signal?

A: There could be several reasons for this problem, which has occurred in other locations, said John Cunningham, the city of Sammamish director of public works.

As part of the sensor system, a wire is cut into the pavement in the shape of a circle or a rectangle near the stop line, Cunningham said. It senses the metal of vehicles and signals a control box on the side of the road to change the light.

This wire, or detection loop, might not be sensitive enough to be triggered by a motorcycle, Cunningham said. Or the detection loop might not be installed in a location that would detect both cars and motorcycles. Also, an amplifier in the control box that increases the strength of signals from the detection loop — much like the antenna on a cellphone — might not be working properly.

Solutions could include replacing the detection loop with a larger or more sensitive model, adjusting the sensitivity level on the amplifier or posting a sign telling motorcyclists where to stop in order to tip off the sensor.

Another reason this is happening could be simply that motorcyclists aren't stopping where they would stop if driving a car, Cunningham said. In that case, motorcyclists might try stopping before the stop line. Or, motorcyclists can try riding in the wheel tracks, said Officer Greg Grannis, Bellevue police spokesman. In the meantime, the city of Sammamish has asked King County, which maintains the signals, to check out the situation.

Early warning

Bellevue: Expect daytime closures of the eastbound Interstate 90 car-pool lane between the Interstate 405 interchange and 150th Avenue Southeast Monday through Friday from 6 a.m. to 2 p.m. Expect closures of the westbound car-pool lane in the same area Monday through Friday from 10 a.m. to 4 p.m.

The southbound lanes of 112th Avenue Northeast will be closed from Northeast Sixth Street to Northeast Eighth Street Monday through Thursday from 9 p.m. to 6 a.m. due to construction at the Bravern development.

Expect intermittent lane closures on Southeast 63rd Street at Lakemont Boulevard weekdays due to construction.

Kirkland: Expect closures of up to two lanes in each direction of I-405 through Kirkland Monday through Thursday nights for paving. The first lane will close at 7 p.m. each night. All southbound lanes will reopen by 5 a.m., all northbound lanes by 6 a.m.

Expect periodic closures of the northbound car-pool lane between Northeast 124th and Northeast 132nd streets except this afternoon and during evening rush hours.

Expect periodic closures between 9 p.m. and 5 a.m. of I-405 southbound onramps and offramps at the Northeast 124th Street interchange Monday through Thursday. Detours will be in place.

Anne Kim: 206-464-2591 or akim@seattletimes.com