Knowledge Base

Grote's Answer

All motor vehicle lamps are required to meet federal specifications regulating the brightness of the lamps. These regulations require that each lamp be designed to meet certain intensity values at various angles. The words “candlepower” and “brightness” are popular terms for the technical term luminous intensity. Intensity is measured in units of Candela, and has no meaning when applied to a lamp as a whole. Intensity can only be measured at specific angles.

The federal regulations for most lamps require that the lamp be tested at 15 to 20 specific angular locations, called test points. At each of these test points, the lamp is required to have a luminous intensity greater than a certain minimum candela value. Often, that intensity must also be less than a certain maximum candela value as well. When evaluating the performance of a lamp, all of these test points must be considered. Looking at the candela value at a single test point is not sufficient to understand the overall performance of a lamp.

All Grote lamps are designed to exceed the appropriate federal regulations for their specific functions.

Other factors also play a role in how bright a lamp appears to a driver’s eyes. Many people have commented that LED lights seem brighter than standard incandescent lamps. Some preliminary studies indicate that this may be true, and that an LED lamp may appear brighter to a human eye even when it’s measured intensity is identical to that of an incandescent lamp.