In the United States, what must drivers do at a flashing red traffic signal?

In the United States, drivers facing a flashing red traffic signal must stop, then proceed when safe.

A flashing red indication is treated like a stop sign. The driver must come to a complete stop at the marked stop line, before the crosswalk, or before entering the intersection if no line or crosswalk is present. After stopping, the driver may continue only when the way is clear and right-of-way rules are followed.

This signal is different from a flashing yellow indication, which normally tells drivers to proceed with caution without requiring a complete stop. Flashing red signals may be used when a traffic light is operating in a special mode, such as during low-traffic periods, or when part of the signal system is malfunctioning.

The exact rules can be supplemented by local law and signs. Pedestrians, cyclists, and other vehicles still retain applicable priority, so stopping alone does not make entering the intersection safe.