Editing Retroreflector (section)

===For signs===
[[File:I-90 and I-190 at Cumberland Ave northbound exit (February 2024).jpg|thumb|[[Retroreflective sheeting]] on highway signs and pavement markings]]
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. Retroreflective traffic sign faces are manufactured with glass beads or prismatic reflectors embedded in a base sheeting layer so that the face reflects light, therefore making the sign appear more bright and visible to the vehicle operator under darkened conditions. According to the United States [[National Highway Traffic Safety Administration]] (NHTSA), the Traffic Safety Facts 2000 publication states the fatal crash rate is 3-4 times more likely during nighttime crashes than 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 require that headlights be turned on in inclement weather such as rain and snow. According to the United States [[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.

The FHWA's [[MUTCD|Manual on Uniform Traffic Control Devices]] requires that signs be either illuminated or made with retroreflective sheeting materials, and though most signs in the U.S. are made with retroreflective sheeting materials, they degrade over time. Until now, there has been little information available to determine how long the retroreflectivity lasts. The MUTCD now requires that agencies maintain traffic signs to a set of minimum levels but provide a variety of maintenance methods that agencies can use for compliance. The minimum retroreflectivity requirements do not imply that an agency must measure every sign. Rather, the new MUTCD language describes methods that agencies can use to maintain traffic sign retroreflectivity at or above the minimum levels.

In [[Canada]], [[aerodrome]] lighting can be replaced by appropriately colored retroreflectors, the most important of which are the white retroreflectors that delineate the runway edges, and must be seen by aircraft equipped with landing lights up to 2 nautical miles away.<ref>{{cite web|url=http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part3-301-155.htm#301_07|title=Transport Canada CARs 301.07|website=tc.gc.ca|access-date=6 April 2018}}</ref>