IT’S ALL ABOUT SAFETY

Safe and efficient highways are a benefit to 

the motoring public and to the health and 

viability of a community. 

Providing retroreflective signing is important 

for reducing the higher nighttime crash rates. 

Signs that have sufficient retroreflectivity 

during nighttime conditions are especially 

beneficial to older road users.

MORE INFORMATION

Additional information regarding 

nighttime visibility can be found at:

www.fhwa.dot.gov/retro

This web site includes:

•	 Regulations/Standards

•	 Technical Guidance

•	 Implementation Tools

•	 Frequently Asked Questions

•	 Funding Assistance

•	 Research

KNOW YOUR RETRO

SIGN

RETROREFLECTIVITY

REQUIREMENTS

(Revised 2013)

FHWA-SA-08-001

An Overview
NIGHT TRAVEL AND CRASHES

One of the Federal Highway Administration’s (FHWA) 

primary missions is to improve safety on the Nation’s 

roadways. Approximately 40,000 people have been 

killed on American roads during each of the past 10 

years. While only one-quarter of all travel occurs at 

night, about half of the traffic fatalities occur during 

nighttime hours. To address this disparity, FHWA has 

established traffic sign retroreflectivity standards.

Nighttime visibility of traffic control devices is 

becoming increasingly important as our population 

ages. By the year 2020, about one-fifth of the 

U.S. population will be 65 years of age or older. In 

general, older individuals have declining vision and 

slower reaction times. Signs that are easier to see 

and read at night can help older drivers retain their 

freedom of mobility and remain independent.

Retroreflective sheeting degrades over time. Signs must 

be periodically assessed or systematically managed to 

comply with minimum retroreflectivity levels.

NATIONAL STANDARDS

The Manual on Uniform Traffic Control Devices 

(MUTCD) is the national standard for all traffic 

control devices (such as signs, signals, and markings) 

on any street or highway open to public travel. The 

MUTCD can be accessed at the following web page: 

http://mutcd.fhwa.dot.gov/.

The MUTCD standard requires signs to be either 

illuminated or made with retroreflective sheeting 

materials. Most signs in the United States. are 

made with retroreflective sheeting materials, which 

degrade over time and therefore have a limited 

useful life. 

The MUTCD also includes a standard requiring 

agencies to use an assessment or management 

method that is designed to maintain sign 

retroreflectivity at or above certain levels.

FLEXIBILITY

The MUTCD retroreflectivity standard not only 

promotes safety for the motoring public but 

also provides flexibility for agencies to choose a 

maintenance method (or methods) that best fits their 

specific conditions.

Contrary to initial impressions, the minimum 

retroreflectivity language does not require that 

agencies measure every sign. Rather, MUTCD Section 

2A.08 describes numerous methods that agencies 

can use to maintain traffic sign retroreflectivity. One 

method, a combination of methods, or a method 

based upon an engineering study tied to the 

minimum levels in MUTCD Table 2A-3 may be used.

Agencies have until June 

14, 2014 to establish and 

implement a sign assessment 

or management method to 

maintain minimum levels of 

retroreflectivity for regulatory 

and warning signs. Agencies also 

are required to incorporate guide 

signs, including overhead mounted guide signs, into 

their maintenance method. However, no compliance 

date is specified for guide signs, so agencies must 

decide when to incorporate those signs into their 

methods as resources permit. When signs are found 

to be below the minimum retroreflectivity levels, they 

should be replaced, but it is up to each agency to 

decide when the replacement occurs.

RETROREFLECTIVE

SHEETING MATERIALS

When selecting sheeting for new signs, agencies 

should consider the standard for maintaining 

signs to a minimum level of retroreflectivity as 

found in Section 2A.08 of the 2009 Edition of the 

MUTCD. One important element of this standard 

is that Engineer Grade sheeting shall not be used 

for warning signs or for white legend on green 

backgrounds.

Even though a particular type of sheeting might 

initially meet the minimum retroreflectivity levels 

when new, it might quickly degrade to below the 

minimum retroreflectivity levels. The use of higher 

performance sheeting, even though it has a higher 

initial cost, might have a lower life-cycle cost.

The 2011 Traffic Sign Retroreflective Sheeting 

Identification Guide can be found at: 

http://safety.fhwa.dot.gov/roadway_dept/

night_visib/sign_visib/sheetguide

3.0

2.5

2.0

1.5

1.0

0.5

Year 2010 Fatalities per 100 Million

0.0

Vehicle Miles Traveled

Nighttime Daytime

Source: NHTSA Traffic Safety Facts (2010)

KNOW

YOUR

RETRO

Collection of example

calibration signs

Comparison panel

on warning sign