ELTEC’s RRFB Progressive Night Dimming
On January 9, 2012 the FHWA clarified and specified that Class 1 (yellow) lights are to be used in all RRFB (Rectangular Rapid Flashing Beacon) pedestrian crossings. The initial FHWA memo dated July 16, 2008 states that the RRFB light intensity “shall meet the minimum specification of Society of Automotive Engineers (SAE) standard J595…” The SAEJ595 standard has three light classifications: Class 1 at 200 cd/candela (a candela is the light output of one candle) used on authorized emergency vehicles (police cars, fire trucks, ambulances); Class 2 at 50 cd for maintenance vehicles; Class 3 at 25 cd used with service vehicles (indoor non-highway use: airport carts, forklifts, etc).
The number of LED’s used or the size of the light head surface area does not determine the signal brightness; the type of LED along with the style of the reflector used determines the light intensity. To ensure the RRFB signal meets the SAEJ595 Class 1 brightness level, ask for the certification from your RRFB system supplier.
ELTEC has always used Class 1 RRFB LED’s. Due to the high intensity of the light output of Class 1 signals, some DOT’s and municipalities are requiring the RRFB signals be dimmed at night. Many emergency vehicles with class 1 light heads are equipped with a switch to lower the light intensity at night. ELTEC offers 6-stage gradual dimming reducing the brightness by 50% to 100 cd’s at night.