The power of a car engine is measured by horsepower - the more the better. The same
can be said for reflective material, which is measured by candle power (cd/lux/m²).
There is a clear relationship between retroreflective performance of a surface and
the distance at which it can be seen. According to 3M data, the retroreflective
performance level (candle power) of white clothing is 0.1 - 0.3 , a license plate's
performance level is at 50 and typical retroreflective silver fabric has a performance
level of 500.
As the following chart depicts, with increasing retroreflective performance, sight
distance also increases, clearly demonstrating that reflective materials allow for
optimal visibility during low light level conditions. However, not all reflective
materials are the same, as there are reflective materials available that range from
65-600 candle power.