StacksVerified U.S. federal law reference

49 CFR Part 234, Appendix B — Alternate Methods of Protection Under 49 CFR 234.105(c), 234.106, and 234.107(c)

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov
Flagger for each direction of trafficPolice officer presentFlagger present, but not one for each direction of trafficNo flagger/no police
False ActivationNormal SpeedNormal SpeedProceed with caution—maximum speed of 15 mphProceed with caution—maximum speed of 15 mph.
Partial Activation*Normal SpeedNormal SpeedProceed with caution—maximum speed of 15 mphProceed with caution—maximum speed of 15 mph.
Activation Failure**Normal SpeedNormal SpeedProceed with caution—maximum speed of 15 mphStop: Crewmember flag traffic and reboard.

*Partial activation—full warning not given.

Non-gated crossing with one pair of lights designed to flash alternatively, one light does not work (and back-lights from other side not visible).

Gated crossing—gate arm not horizontal; or any portion of a gate arm is missing if that portion had held a gate arm flashing light.

**Activitation failure includes—if more than 50% of the flashing lights on any approach lane not functioning; or if an approach lane has two or more pairs of flashing lights, there is not at least one pair operating as intended.