Traffic signals lose power for many reasons, but there's only one way to drive through an intersection when the signal goes dark. Treat it like a four-way stop, unless a flagger, a police officer, or a firefighter directs you to do otherwise, you are required to stop and yield the right-of-way in accordance with the law. (WA State law RCW 46.61.183.)
Keep in mind that the law says who must yield the right-of-way, it does not give anyone the right-of-way.
Here are the basic right-of-way rules for vehicles approaching all-way stops:
When two vehicles approach or enter an intersection from different roadways at approximately the same time, the driver of the vehicle on the left shall yield the right-of-way to the vehicle on the right. In other words, when two vehicles stop together at the intersection, if there is a vehicle to your right, it goes first.
Drivers turning left must yield to oncoming vehicles going straight ahead.
Drivers must do everything possible to keep from striking a pedestrian or another vehicle, regardless of the circumstances.
Overhead Electronic Message Signs
An overhead electronic message board is an electronic sign often used on road ways to give travelers information.
These signs are controlled from City Hall and display traffic-related information such as:
warn of traffic congestion
roadwork zones or speed limits
current or planned road closures or major events
The boards display current travel times through downtown along three parallel routes: