Daniel Stern, Driving Vision News
As previously reported in DVN, the U.S. National Highway Traffic Safety Administration has requested public comments—due soon on February 16!—on a proposal to upgrade the US NCAP (New Car Assessment Program) protocol. Under the plan, NCAP points would be awarded to vehicles with better-than-minimally-legal low beam headlamps, among other crash-avoidance features. The proposed NCAP low beam test method looks at the performance of a vehicle's low beam headlamp system in situ. That is: both lamps, installed on the vehicle, aimed per manufacturer specifications, and equipped with a seasoned (i.e., used) bulb. This differs substantially from the method used to test legal compliance of headlamps, wherein a goniophotometer in a lab measures the performance of a single headlamp, aimed to a regulatory specification and equipped with a dimensionally exact accurate-rated (similar to the UN "Etalon") bulb. Because a potentially imperfect bulb is employed, the headlamps' mounting height and vehicle voltage supply factor in, and manufacturer's aim specification is used, the proposed NCAP method might reasonably be called more representative than an idealised lab test of the lighting performance a driver will experience in the car on the road—at least theoretically.
But does the proposed NCAP method really generate a more-or-less realistic snapshot of actual headlamp performance? Or does it merely exchange the blind spots of a lab test for a different set of blind spots? And if it's the latter, do the NCAP proposal's blind spots exclude safety-related factors worth including?