At an intersection with a flashing red traffic light, you should:

A flashing red light is treated exactly like a stop sign: come to a complete stop at the stop line (or before the intersection), yield to any traffic in or approaching the intersection, then proceed when safe. A flashing yellow light is treated like a yield sign or a caution signal: slow down, proceed with care, and yield to any conflicting traffic. Flashing signals are typically used at intersections where full traffic signals are temporarily disabled, at quiet intersections during overnight hours, or as part of railroad warning systems. Sitting and waiting at a flashing red until it turns green will keep you sitting forever because the signal is operating as designed.