Nighttime Visibility

About half of traffic fatalities occur at night, although only about one quarter of travel occurs after dark. Although intoxication and fatigue contribute to the high rate of nighttime crashes, nighttime driving is inherently hazardous because of decreased driver visibility.

Adequately maintained retroreflective signs and pavement markings improve highway safety and prevent roadway departure crashes by bouncing light from vehicle headlights back toward the vehicle and the driver's eyes, making the signs and markings appear brighter and easier to see and read. Because the retroreflective properties of traffic control devices deteriorate over time, highway agencies need to actively manage the maintenance of signs and pavement markings in order to ensure that they are clearly visible at night.

Roadway lighting is another means to increase visibility for drivers and other roadway users. Properly designed roadway lighting allows road users to quickly assess roadway conditions and creates a safe environment within the roadw ay vicinity. New technologies to reduce the long-term costs of lighting need to be balanced with understanding  and addressing the needs of the road user.

Use the links below to obtain pertinent information related to these three important areas that impact nighttime visibility. The subject areas are grouped as follows:

Sign Retroreflectivity

Pavement Markings

Roadway Lighting

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Program Contact

Cathy Satterfield

What's New

Design Criteria for Adaptive Roadway Lighting, PUBLICATION NO. FHWA-HRT-14-051 JULY 2014 new

Median Barriers on Divided Highways Regardless of Access Type new

ET-Plus W-Beam Guardrail Terminal Memorandum new

FHWA Resource Charts, July 2013

FHWA Roadway Lighting Handbook, August 2012

RwD Strategic Plan, April 2013

Updated Guidance on Sign Retroreflectivity, April 2013

Clarifying Guidance on Daytime Luminance, January 2013

Guidance for the Selection , Use and Maintenance of Cable Barrier Systems, November 2012