Flashing Light Signals indicate the approach of a train and require a complete stop by the highway user. When indicating the approach or presence of a train at a highway-rail grade crossing flashing light signals are activated. Flashing light signals are mandatory with gates. When both are activated, the gate arm light nearest the tip will be illuminated continuously and the other two lights shall flash alternately in unison with the flashing light signals. A bell may be included in the assembly and operated in conjunction with the flashing lights.
Bells are a particularly suitable warning for pedestrians and bicyclists.
This is done by providing a source of standby power at the crossing. Storage batteries are the principal source of standby power for crossing warning systems. Due to the requirement of standby power to last as long as 48 hours in some states, low wattage bulbs must be used in the flashing light signals. The small wattage bulbs, sometimes as low as 16-18 watts, require a highly efficient light unit. Flashing Light Signals are found at all types of public highway-rail grade crossings.