Traffic

Here’s Why Some Traffic Lights Aren’t Turning Green for Bicycles

A set of traffic lights near Columbia Pike isn’t working for bicycles, officials say.

The Department of Environmental Services (DES) confirmed that traffic signal at the intersection of S. Walter Reed Drive and 11th Street S. is not detecting bicycles.

DES crews discovered this week that an underground conduit collapsed, effectively disabling the sensors that detect bicycles waiting to cross Walter Reed Drive and trigger a green light.

“There’s currently no bike lane detection because we weren’t able to get the cable from the controller to this side of the intersection due to the collapsed conduit,” DES spokesman Eric Balliet tells ARLnow.

“Staff are working on how to address the issue, but we don’t have an estimate at this time for when a fix can be implemented,” he said.

In the meantime, the department reconfigured the intersection to give a green light to the contraflow bike lane on 11th Street during each light cycle. In a contraflow bike lane, bicyclists ride against the flow of traffic.

The department found the problem after cyclists — including Arlington County official Henry Dunbar — noted on social media earlier this month that some intersections hadn’t turned green for them.

Balliet said crews inspected N. Veitch Street and Lee Highway on Wednesday after the online complaints and found no issues.

No other intersections have known issues either, but Bailliet said in an emailed statement that some intersections use a new vehicle detection technology and it can be finicky:

The newer detection cameras the County uses for vehicular detection can also detect bicycles, but the system requires the bicycle to approach the intersection in a vehicular or bicycle lane in order to be detected. If the bicycle doesn’t adhere to the stop bar area or rides in an atypical pattern, the cameras will likely not detect the bicycle as the zones are set up with the stop bar as a reference and can only be triggered from travel in a single general direction.

He added that cameras will also fail to detect bicycles on sidewalks and riders need to continue pushing walk buttons to cross safety.

DES asks travelers to report intersection problems to the county’s online system so crews can investigate.

Images via Google Maps