*updated in 2013 to reflect current MUTCD compliance dates

FHWA-SA-07-020 (Revised 2013)

T his document is referenced in Section 2A.08 of the Manual on Uniform Traffic Control Devices (MUTCD). Please be sure to review the methods discussed on pages two and three, along with the related 

procedures that make each method reliable and meaningful in its use to maintain signs above the minimum 

retroreflectivity levels. A full report on these methods can be found at www.fhwa.dot.gov/retro.

SCHEDULE

Method:

Agencies have until 

June 14, 2014 to implement 

and continue to use an 

assessment or management 

method that is designed 

to maintain regulatory and 

warning sign retroreflectivity 

at or above the minimum 

levels in Table 2A–3 of the 

2009 MUTCD.

Although guide signs are 

included in the minimum 

retroreflectivity levels table, 

there is not a specified 

compliance date for guide 

signs (including street name 

signs) to be addressed by an 

agency’s method. Guide signs 

are to be added to an agency’s 

management or assessment 

method as resources allow.

Sign Replacement:

Agencies need to replace 

any sign they identify as not 

meeting the established 

minimum retroreflectivity 

levels. Agencies’ schedules for 

replacing signs are based on 

resources and relative priorities 

rather than specific compliance 

dates.

KNOW

YOUR

RETRO

2007* Retroreflectivity

Traffic signs provide important 

information to road users. To be 

effective, traffic sign visibility must 

be maintained during daytime and 

nighttime conditions. In addition to 

Section 2A.08, the MUTCD addresses 

sign visibility in several other places, 

including Sections 1A.03, 1A.04, 

1A.05, 2A.06, 2A.07, and 2A.22. 

These sections address factors such 

as uniformity, design, placement, 

operation, and maintenance. 

The Standard in Section 2A.08 

requires agencies to use a maintenance 

method that is designed to maintain 

traffic signs at or above minimum 

levels of retroreflectivity in Table 2A-3. 

Including Table 2A-3 in the MUTCD 

does not imply that an agency must 

measure the retroreflectivity of every 

sign. Rather, the MUTCD summarizes 

five methods that agencies can use to 

maintain traffic sign retroreflectivity at 

or above the minimum levels. These 

methods are listed in Section 2A.08 

and are discussed on pages two and 

three of this document. The Standard 

promotes safety while providing 

sufficient flexibility for agencies to 

choose one or more maintenance 

methods that best match their specific 

conditions.

This Standard does NOT imply all 

signs need to be replaced. The intent 

is to identify and replace signs that no 

longer meet the needs of nighttime 

drivers.

The MUTCD language recognizes 

that there may be some individual 

signs that do not meet the minimum 

retroreflectivity levels at a particular 

point in time. Reasons for this include 

vandalism, weather, or damage due 

to a crash. As long as the agency 

is using one of the methods (with 

appropriate procedures) to maintain 

their signs, they are considered to be 

in compliance with this Standard. 

The methods recommended in 

the MUTCD are broken into two 

categories: management methods 

and assessment methods. Assessment 

methods involve sending personnel 

out to examine and assess the 

retroreflective performance of signs. 

Some agencies may find this approach 

to be more labor intensive and turn 

to management methods as an 

alternative. Management methods 

may require less field work (or none 

at all in some cases) but may also 

result in replacing some signs that 

still have useful life left in terms of 

retroreflectivity. These recommended 

methods are discussed on pages two 

and three of this document and are 

described in detail in a full report 

entitled “Methods for Maintaining 

Traffic Sign Retroreflectivity,” available 

at www.fhwa.dot.gov/retro.

Maintaining Traffic Sign

www.fhwa.dot.gov/retro Page 1
Page 2 www.fhwa.dot.gov/retro

ASSESSMENT METHODS

Assessment methods involve evaluating individual signs within an agency’s jurisdiction. There are two basic 

assessment methods identified in the 2009 MUTCD: visual nighttime inspection and measured sign retroreflectivity.

1. VISUAL NIGHTTIME INSPECTION METHOD

In the visual nighttime inspection method, on-the-fly assessments of retroreflectivity are made by an inspector during 

nighttime conditions. The following are keys to successfully implementing the visual nighttime inspection method:

 A. Develop guidelines and procedures for inspectors to use in conducting the nighttime inspections and train 

inspectors in the use of these procedures.

 B. Conduct inspections at normal speed from the travel lane(s).

 C. Conduct inspections using low-beam headlights while minimizing interior vehicle lighting.

 D. Evaluate signs at typical viewing distances so that adequate time is available for an appropriate driving response.

One or more of the following procedures should be used to properly implement this method:

Calibration Signs Procedure (for Visual Nighttime Inspection Method)

Calibration signs have known retroreflectivity levels at or above minimum levels. These calibration signs are set up 

so the inspector views the calibration signs in a manner similar to nighttime field inspections. A trained inspector 

views calibration signs prior to conducting the nighttime inspection described in 1 A-D above. The inspector uses 

the visual appearance of the calibration signs to establish the evaluation threshold for that night’s inspection. 

During the nighttime drive-through inspection of in-service signs, if the inspector believes a sign appears to be 

less bright than the calibration signs viewed earlier, the in-service sign should be replaced. The following factors 

provide additional information on the use of this procedure:

•	 Calibration signs are needed for each color of sign in Table 2A-3 of the 2009 MUTCD.

•	 Calibration signs are viewed at typical viewing distances using the inspection vehicle.

•	 Calibration signs need to be properly stored between inspections so that their retroreflectivity does not 

deteriorate over time.

Comparison Panels Procedure (for Visual Nighttime Inspection Method)

Comparison panels are fabricated with retroreflectivity levels at or above the minimum levels. The trained 

inspector makes an initial nighttime visual inspection described in 1 A-D above to identify signs that are obviously 

above or below the minimum retroreflectivity values as well as those the inspector considers to be marginal. 

Those signs designated as obviously below the minimum retroreflectivity values are scheduled for replacement. 

For signs considered marginal, a supplementary nighttime inspection is conducted by attaching a comparison 

panel to the in-service sign. With a flashlight, the inspector views the in-service sign along with the comparison 

panel to determine whether the in-service sign appears brighter or less bright than the comparison panel. If the 

in-service sign appears less bright than the comparison panel, the in-service sign should be replaced.

Consistent Parameters Procedure (for Visual Nighttime Inspection Method)

For this procedure, nighttime inspections described in 1 A-D above are conducted by a trained inspector under 

similar factors that were used in the research to develop the minimum retroreflectivity levels. These traits include:

•	 Using an inspector who is at least 60 years old.

•	 Using a sport utility vehicle or pick-up truck from which to make the observations.

•	 Using a model year 2000 or newer vehicle.

The trained inspector makes a judgment call as to whether an in-service sign meets their nighttime driving needs. 

Those signs judged not to meet the visual driving needs should be replaced. Note, the three factors listed here 

are specific to this procedure and are not required for visual nighttime inspections using the calibration signs 

procedure or the comparison panels procedure.

2. MEASURED SIGN RETROREFLECTIVITY METHOD

In this method the retroreflectivity of a sign is measured with a handheld or mobile retroreflectometer and directly 

compared to the minimum level appropriate for that sign. ASTM E1709, Standard Test Method for Measurement 

of Retroreflective Signs Using a Portable Retroreflectometer, provides the standard method for measuring sign 

retroreflectivity with handheld instruments. If the measured sign retroreflectivity value is less than the appropriate level 

in Table 2A-3, the sign should be replaced.
www.fhwa.dot.gov/retro Page 3

OTHER METHODS

Other assessment or management methods that are developed based on engineering studies can be used as 

long as they are designed to maintain minimum levels in Table 2A-3 of the 2009 MUTCD, as stated in the MUTCD 

Standard statement in Section 2A.08.

MANAGEMENT METHODS

Management methods provide an agency with the ability to maintain sign retroreflectivity without having to 

physically inspect each individual sign. While it is not required by the MUTCD, some agencies have chosen to 

determine the sheeting type and age or retroreflectivity levels of existing signs before using a management method. 

This is done by those agencies to prevent signs currently near or below minimum levels from being left in place 

several additional years. The 2009 MUTCD identifies three management methods: 

1. EXPECTED SIGN LIFE METHOD

In this method, the agency monitors the age of individual signs and replaces them before they are expected to 

degrade below the minimum levels in Table 2A-3 of the 2009 MUTCD. The retroreflectivity life of a sign may vary by 

such factors as type of sheeting, geographic location, color, and direction the sign faces. This method depends on 

knowing the age and type of sheeting used for the signs. Agencies may choose to consider weathering deck results, 

measurements of field signs, sign sheeting warranties, or other criteria as the basis for the expected sign life. A 

common approach for identifying the age of individual signs uses a label on the sign to mark the year of fabrication 

or installation. Agencies can also use sign management systems to track the age of individual signs.

2. BLANKET REPLACEMENT METHOD

In this method, an agency manages signs in groups rather than as individual signs. An agency may choose to 

group signs by geographic area, roadway corridor, type of sheeting, or sign category (e.g., warning signs). The sign 

replacement interval is based on the expected sign life for the sign sheeting in the group with the shortest expected 

life. This method typically obligates an agency to replace all of the designated signs within a group, even if a sign 

was recently replaced due to issues such as vandalism or damage.

3. CONTROL SIGNS METHOD

In this method, agencies monitor the performance of a control sample of signs that represent a larger group of 

signs. Agencies track the retroreflectivity of the control signs to determine when replacement of the larger group is 

necessary based on the performance of the control signs. 

•	 Agencies should develop a sampling plan to determine the appropriate number and type of control signs 

needed to represent the larger group of signs. Samples should represent the entire group, including such 

factors as sign sheeting type and color.

•	 Control signs may be actual signs in the field or signs in a maintenance yard (for convenience).

•	 Agencies should monitor the retroreflectivity of the control signs using an assessment method.
Excerpt from Part 2 of the 2009 MUTCD

Section 2A.08 Maintaining Minimum Retroreflectivity

Support:

01 Retroreflectivity is one of several factors associated with 

maintaining nighttime sign visibility (see Section 2A.22).

Standard:

02 Public agencies or officials having jurisdiction shall use 

an assessment or management method that is designed to 

maintain sign retroreflectivity at or above the minimum 

levels in Table 2A-3.

Support:

03 Compliance with the Standard in Paragraph 2 is achieved 

by having a method in place and using the method to 

maintain the minimum levels established in Table 2A-3. 

Provided that an assessment or management method is being 

used, an agency or official having jurisdiction would be in 

compliance with the Standard in Paragraph 2 even if there 

are some individual signs that do not meet the minimum 

retroreflectivity levels at a particular point in time.

Guidance:

04 Except for those signs specifically identified in Paragraph 6, one 

or more of the following assessment or management methods 

should be used to maintain sign retroreflectivity:

A. Visual Nighttime Inspection—The retroreflectivity of 

an existing sign is assessed by a trained sign inspector 

conducting a visual inspection from a moving vehicle during 

nighttime conditions. Signs that are visually identified by the 

inspector to have retroreflectivity below the minimum levels 

should be replaced.

B. Measured Sign Retroreflectivity—Sign retroreflectivity 

is measured using a retroreflectometer. Signs with 

retroreflectivity below the minimum levels should be 

replaced.

C. Expected Sign Life—When signs are installed, the 

installation date is labeled or recorded so that the age 

of a sign is known. The age of the sign is compared to 

the expected sign life. The expected sign life is based on 

the experience of sign retroreflectivity degradation in a 

geographic area compared to the minimum levels. Signs 

older than the expected life should be replaced.

D. Blanket Replacement—All signs in an area/corridor, or of 

a given type, should be replaced at specified intervals. This 

eliminates the need to assess retroreflectivity or track the life 

of individual signs. The replacement interval is based on the 

expected sign life, compared to the minimum levels, for the 

shortest-life material used on the affected signs.

E. Control Signs—Replacement of signs in the field is based on 

the performance of a sample of control signs. The control 

signs might be a small sample located in a maintenance 

yard or a sample of signs in the field. The control signs are 

monitored to determine the end of retroreflective life for the 

associated signs. All field signs represented by the control 

sample should be replaced before the retroreflectivity levels 

of the control sample reach the minimum levels.

F. Other Methods—Other methods developed based on 

engineering studies can be used.

Support:

05 Additional information about these methods is contained 

in the 2007 Edition of FHWA’s “Maintaining Traffic Sign 

Retroreflectivity” (see Section 1A.11).

Option:

06 Highway agencies may exclude the following signs from the 

retroreflectivity maintenance guidelines described in this 

Section:

A. Parking, Standing, and Stopping signs (R7 and R8 

series)

B. Walking/Hitchhiking/Crossing signs (R9 series, R10-1 

through R10-4b)

C. Acknowledgment signs

D. All signs with blue or brown backgrounds

E. Bikeway signs that are intended for exclusive use by 

bicyclists or pedestrians

2009 MUTCD

Section Number(s)

2009 MUTCD 

Section Title Specific Provision Compliance Date

2A.08

Maintaining 

Minimum

Retroreflectivity

Implementation and continued use of an assessment or 

management method that is designed to maintain regulatory 

and warning sign retroreflectivity at or above the established 

minimum levels (see Paragraph 2)

June 14, 2014

(date established 

in Revision 2 

to 2009 MUTCD)*

* Types of signs other than regulatory or warning are to be added to an agency’s management or assessment method as resources allow.

Note: The referenced document is actually 

this four-page brochure you are reading.