Railroad crossing flashing lights

How to read it

The MUTCD requires the signal to show approaching traffic two red lights in a horizontal line, flashing alternately, each lamp 35 to 65 times a minute, on a post that also carries a crossbuck and, where there is more than one track, a number of tracks plaque. Bells may ring with them. On a gated crossing the same lights flash on the gate arm. State manuals treat the flashing lights as a signal to stop: Pennsylvania's lists flashing red lights among the signals of an approaching train at which drivers are required to stop, and Florida's says anyone approaching a crossing must stop if the warning devices are flashing. This page describes the national standard and isn’t legal advice; what a driver must do at a crossing is set by state law.

Also searched as: flashing red lights railroad crossing, railroad crossing lights, train signal lights.

How much warning the lights give

Federal rules (49 CFR 234.225) require a crossing warning system to start at least 20 seconds before a through train reaches the crossing. The state manuals put the same figure to drivers: Michigan's says that once the lights and gates activate, or the train's horn sounds, there are about 20 seconds before the train arrives, and Florida's calls 20 seconds the least time a train takes to reach the crossing after the lights begin flashing.

The train's horn at the same crossing

The lights are not the only warning. Under the FRA's train horn rule (49 CFR Part 222), a train approaching a public crossing sounds its horn in a fixed pattern of two long blasts, one short and one long, repeated or held until the locomotive is in the crossing. The horn starts 15 to 20 seconds before the crossing, and no more than a quarter of a mile before it for trains over 60 mph. Where a quiet zone has been set up, marked by a NO TRAIN HORN plaque, the horn is not sounded routinely.

What changed in the 2023 MUTCD

The rules moved from Section 8C.02 of the 2009 edition to Section 8D.02 of the 11th edition (2023), which adds guidance on the layout: the two lights about 30 inches apart, mounted 8 to 9 feet above the road, and at least one pair of lights for each approach lane.