Know the rules when traffic lights go out

With the onset of summer today, the likelihood of severe weather causing power outages tends to increase.

Traffic signals rely on the electrical grid for power, so it is not uncommon for signals to go dark when the power goes out. Additionally, heavy rain or lightning strikes can damage signals’ electrical circuitry, causing signals to malfunction and go into flashing mode.

When traffic lights are dark or flashing red, motorists sometimes make mistakes. Knowing the rules when signals malfunction can prevent a crash. They are:

n Signals flashing all red lights: When a traffic signal malfunctions but has power, it often reverts to a flashing mode. In some places, signal lights go into a scheduled flash mode daily to reduce delay and electrical costs.

When drivers approach a flashing red signal light, they must come to a complete stop. Sometimes, the intersection flashes red in all directions, making the intersection operate like a four-way stop. But at some intersections, the lights may flash yellow for the main roadway, making the intersection like a two-way stop, which saves fuel and reduces unnecessary stops. Always make sure it is safe to proceed before entering an intersection since crossing traffic might not be required to stop.

n Signal flashing red and yellow lights: There is no need to come to a stop when approaching a flashing yellow light, but be alert for drivers entering and proceed with caution. Follow the same rules as any two-way stop intersection, including yielding to oncoming traffic when turning left, and yielding to pedestrians in crosswalks.

n Signal lights all dark: During planned or prolonged power outages, stop signs may sometimes be installed to control traffic until the signal is repaired or power is restored. But during unplanned power outages, stop signs are usually not installed.

When a traffic signal is completely unlit and no stop signs are present, and the signal lights are not wrapped in cloth or other material, the intersection legally becomes an uncontrolled intersection. As with any uncontrolled intersection, right-of-way rules still apply. If approaching a signal system without power and the lights are not covered with cloth:

n Reduce speed and prepare to stop.

n Vehicles have right of way in the order in which they arrive, regardless of which road they arrive from. In heavy traffic, this will usually necessitate a complete stop.

n If two vehicles arrive at the intersection at approximately the same time, the vehicle on the left must yield to the vehicle on the right, and left turns must yield to oncoming traffic.

Signals in flashing mode can come back into normal operation at any time and without warning, even when repair crews are not present. The flashing red light may change to a solid red, and drivers often fail to notice the difference and run the red light. Proceeding on a solid red light is always illegal and can lead to a serious crash. Be alert and make sure that the light is still flashing red and that it is safe to enter before entering the intersection.

During power outages, Washington County often receives requests to install temporary stop signs at signalized intersections that are without electrical power. Washington County’s policy is to not install temporary stop signs during a power outage because power is usually restored in a short period of time and dispatching equipment and personnel to the site is not beneficial.

During widespread power outages, this problem becomes magnified because of the number of intersections affected. Also, when power is restored, a conflict could exist between the stop sign and the green indication of the traffic signal system unless the controller has been reset to the "red flash" mode. Setting the controller to red flash mode prolongs the traffic problem because the signal cannot resume normal operations when power is restored, and taking a traffic signal out of red flash mode carries numerous risks to traffic safety.

To report a signal malfunction, contact the highway department responsible for the signals. For signals on state highways in Washington County, contact the Minnesota Department of Transportation at 651-234-7500. For signals on county roads, contact Washington County Public Works at 651-430-4300. If the malfunction is an emergency, dial 911.





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