Reflectivity is light reflected from a source to a surface and returned to its original source.
For traffic signs and vehicle operators, the light source is a vehicle’s headlights, where the light is sent to the traffic sign face and then returned to the vehicle operator. Traffic signs are manufactured with Retroreflective sheeting so that the traffic sign is visible at night. Reflective sign faces are manufactured with glass beads or prismatic reflectors imbedded in the sheeting so that the face reflects light, therefore making the sign appear more bright and visible to the vehicle operator. According to the National Highway Traffic Safety Administration (NHTSA), The Traffic Safety Facts 2000 publication the fatal crash rate is 3-4 times more likely during night time crashes then daytime incidents.
A misconception many people have is that Retroreflectivity is only important during night-time travel, however, In recent years, more states and agencies are requiring headlights to be used during inclement weather, such as rain and snow.
According to the Federal Highway Administration (FHWA):
- Approximately 24% of all vehicle accidents occur during adverse weather (rain, sleet, snow and fog)
- Rain conditions account for 47% of weather related accidents. These statistics are based on 14 year averages from 1995 to 2008
No time may be of more importance for motorist to be able to adequately view traffic signs then during these types of weather events.