RRFB Signal Head. The RRFB signal head unit shall consist of two yellow rapidly flashing rectangular-shaped LED indications. The two indications shall be horizontally aligned, and each rectangle shall be 7 inches wide by 3 inches high (which exceeds the MUTCD minimum of 5 inches wide by 2 inches high) with at least 7 inches between them (measured from the nearest edge of one indication to the nearest edge of the other indication). The width of the RRFB housing shall be 22 inches to 24 inches, measured from the outside edges. The height of the RRFB housing shall be 3.75 inches to 4.5 inches, measured from the outside edges. The RRFB signal head assemblies shall be compatible with back-to-back mounting on the pole for dualsided display and allow aiming of the assembly to oncoming traffic. The RRFB signal head shall be equipped with an LED pedestrian confirmation light on the side of the signal housing to indicate to pedestrians when the RRFB signal head is flashing. The RRFB signal head housing shall be black. LED lamp assemblies shall be made in the USA. Lamp optical output shall comply with FHWA ruling 4(09)-24(I) which forbids daytime dimming of RRFB signal heads. The RRFB shall have an operating temperature meeting NEMA specifications. Beacon flashing requirement: RRFBs shall provide 75 flashing sequences per minute. During each 800-millisecond flashing sequence, the left and right RRFB indications shall operate using the following sequence: • The RRFB indication on the left-hand side shall be illuminated for approximately 50 milliseconds. Both RRFB indications shall be dark for approximately 50 milliseconds. • The RRFB indication on the right-hand side shall be illuminated for approximately 50 milliseconds. Both RRFB indications shall be dark for approximately 50 milliseconds. • The RRFB indication on the left-hand side shall be illuminated for approximately 50 milliseconds. Both RRFB indications shall be dark for approximately 50 milliseconds. • The RRFB indication on the right-hand side shall be illuminated for approximately 50 milliseconds. Both RRFB indications shall be dark for approximately 50 milliseconds. • Both RRFB indications shall be illuminated for approximately 50 milliseconds. Both RRFB indications shall be dark for approximately 50 milliseconds. • Both RRFB indications shall be illuminated for approximately 50 milliseconds. Both RRFB indications shall be dark for approximately 250 milliseconds. The flash rate of each individual RRFB indication, as applied over the full flashing sequence, shall not be between 5 and 30 flashes per second to avoid frequencies that might cause seizures. The RRFB shall be rated for Class 1 light intensity output according to the Society of Automotive Engineers (SAE) Standard J595. RRFB shall be equipped with an automatic dimming feature for nighttime use.
