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- FHWA Minimum Levels of Retroreflectivity Ruling became effective January
22, 2008
- Replace non-compliant traffic signs to meet new federal retroreflectivity
standards
- Improve sign brightness and visibility to help meet safety goals
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Fifteen years ago the Congress of the United States
acknowledged the importance of nighttime visibility of
road signs and markings as important safety tools. The
1993 DOT Appropriations Act stated that the "Secretary
of Transportation shall revise the MUTCD to include
a standard for a minimum level of retroreflectivity that
must be maintained for traffic signs and pavement
markings which apply to all roads open to public travel."
The Federal Highway Administration’s Minimum Levels
of Retroreflectivity Ruling for traffic signs went into effect
on January 22, 2008.
Summary of MUTCD Revisions
From January 22, 2008 (the effective date of the ruling) agencies have:
- Four years to implement and continue using an
assessment or management method to maintain
traffic sign retroreflectivity at or above the established
minimum levels.
- Seven years for replacement of regulatory, warning and
ground-mounted signs (except street name signs) that
fail to meet the established minimum levels.
- Ten years for replacement of street name signs and
overhead guide signs that fail to meet the established
minimum levels.
Summary of the Minimum Maintained Retroreflectivity Levels Table
- White copy on overhead guide signs must be made from prismatic sheeting
- White copy on ground mounted street name signs cannot be made from Type I sheeting
- Warning signs (black on yellow or orange) cannot bemade from Type I sheeting
- Regulatory signs (black on white) must retain a
minimum retroreflectivity level of ≥ 50 cd/lx/m2 (while
use of Type I sheeting—with an initial retroreflectivity
value of 70 cd/lx/m2—is allowed, sign life will be short
and may result in poor life cycle value)
- Stop signs (white on red) have a minimum contrast ratio
of ≥ 3:1 (white reflectivity ÷ red reflectivity) (older stop
signs—especially south-facing signs—are at risk of
noncompliance due to ink fading)
Summary of Assessment/Management Methods
Method |
Process |
Advantages |
Disadvantages |
Visual Nighttime Inspection |
Trained sign inspector, moving vehicle |
Quick and inexpensive |
Annual process, not 100% reliable |
|
Measured Retroreflectivity |
Measure signs with a
retroreflectometer |
Extremely accurate |
Annual process, large time and
resource commitment |
Expected Life |
Determine expected life, replace at
end of service life |
Very easy to use and plan, can use
preexisting asset management systems |
Does not consider signs that may fail
early or last longer |
|
Blanket Replacement |
All signs in a corridor or of a specific
type are replaced at specific intervals |
No need to track signs or assess
retroreflectivity, easiest method to
manage |
May replace good signs that do not
necessarily need it |
Control Signs |
Replacement based on performance
of control signs |
Less costly and time consuming than
monitoring all signs in the field |
Creating and setting up appropriate
control environment, sample-based |
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Other Engineering-based method |
Varies with method |
Varies with method |
Varies with method |
For details and additional information about the FHWA Minimum Levels of Retroreflectivity Ruling, check out
www.minimumreflectivity.org. To learn more about bright, durable 3M prismatic reflective sheetings, traffic sign upgrade services and flexible funding programs, contact your 3M representative or contact us.
