RetroreflectivityWhat is it and Why Should I
Care?
Matheu J. Carter, P.E.T2 Engineer
Delaware T2 Center
October 15, 2009
Delaware T2 CenterT2 Centers or LTAPs located in all 50 statesFunded by FHWA and state DOTsMission – promote training, tech transfer, research implementation at local levelDelaware T2 hosted by University of Delaware, part of Delaware Center for Transportation
Matt CarterCurrently, Delaware T2 Engineer, Municipal Engineering Circuit Rider, Safety Circuit RiderProfessional Engineer, licensed in six states20+ year career, civil & env engineering
Bridge, road, utility construction Design consulting Public sector (Director, DPW, Cecil County, MD)
OutlineWhat is retroreflectivity?What is the MUTCD and to whom does it apply?What is the origin of the retroreflectivity standards?What are the standards?What do you need to do and when?What are your options for compliance?What should you be doing now?Why should you take it seriously?
CautionThis is a big topicWhile a good start, this 2-hour webinar alone won’t prepare youSo where else can you turn?
The November 5 APWA CLL will be a big help also FHWA, APWA, ATSSA, NACE, and others have great web
content LTAP or T2 Centers in each state and tribal region – many
are conducting local training in your area
So, what is retroreflectivity?And what is it not?
It is the ability of a material to return light back towards its sourceIt is not mirror-reflectivity, which bounces light off in the opposite directionIt is definitely not diffuse reflection, which scatters the light source – think of a painted wall
So, what is retroreflectivity?These signs have varying retroreflective levels – notice how brightly one returns the light versus the others
Which of the stop signs below do you want at the intersections as your teenage child or grandparent comes home on a rainy night?
Manual on Uniform Traffic Control Devices
The MUTCD is the national standard for all traffic control devices installed on all roads that are open to public travelApplies to TCDs on “any street, highway, or bicycle trail open to public travel” – 23 CFR Part 655 Subpart FMany states have their own MUTCD that meets or exceeds the federal manual
Origin of retroreflectivity standardsGeneral retroreflectivity standards have existed in the MUTCD for some time – Section 2A.081993 DOT appropriations act required standardsMinimum retroreflective requirements established in Revision 2 of the 2003 Edition – Section 2A.09Minimum requirements resulted from research targeted at the reduced reaction times and vision of some older drivers – this becomes important with some of the compliance methods
The standards – Table 2A-3
The standards – Table 2A-3Sheeting types
Beaded (Engineer Grade, Super Engineer Grade, High Intensity)
Prismatic (High Intensity Prismatic, Diamond Grade, etc.)Examples
End Detour (black on orange) – orange ≥ 50 Do Not Enter sign (white on red) – white ≥ 35; red ≥ 7 and
contrast of white to red ≥ 3:1 (wash out concern)
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Exempt signsParking/Standing/StoppingWalking/HitchhikingAdopt-A-HighwayBlue or Brown BackgroundsExclusive Use of Bikes
or Pedestrians
Note: Must still meet otherrequirements in MUTCD(inspections, retroreflective,etc.)
What to do and when?Develop and implement a method or methods
“Compliance with the…Standard 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…even if there are some individual signs that do not meet the minimum retroreflectivity levels at a particular point in time.” Section 2A.09
Effective date of Final Rule – January 22, 20081st compliance deadline– January 2012 (4 yrs)2nd compliance deadline – January 2015 (7 yrs)3rd compliance deadline – January 2018 (10 yrs)
What to do and when?January 2012
Implementation & continued use of an assessment or management method designed to maintain retroreflectivity at or above established minimum retro levels (Table 2A-3)
January 2015 replacement of regulatory, warning, and ground-mounted
guide (except street name) signs identified as failing to meet the minimum retro levels
January 2018 replacement of street name signs and overhead guide signs
identified as failing to meet the established minimum levels.
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The methodsVisual Nighttime Inspection
Calibration Signs Comparison Panels Consistent
Parameters Measured Sign Retro
Expected Sign LifeBlanket ReplacementControl SignsFuture Method Based On Engineering StudyCombination Of Any
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Visual nighttime inspectionTrained inspectorVisual inspection/assessment at nightNeed to tie to minimum values by using
Calibration signs procedure, or Comparison panels procedure, or Consistent parameter procedure
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Visual nighttime inspectionCommon elements of all visual assessment techniques
Properly aim inspection vehicle headlamps http://www.automedia.com/Aiming_Headlights/ccr20010801ha/1 http://www.coolbulbs.com/HID-VISUAL-HEADLIGHT-AIMING-PROCEDURE.pdf
Two-person crew works best Having an inventory in advance is ideal Have evaluation form and criteria Conduct evaluations at roadway speed Use low-beam headlamps
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You “calibrate” your eyes with calibration signs Calibration signs
are near minimum retro
You then evaluate signs as compared to calibration signs
Calibration signs
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Comparison panelsTie to minimum values with comparison panels
Panels are near desired retro Clipped to sign - viewed from distance Evaluate signs compared to panels
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Uses parameters consistent with those used to develop the minimum levels
Inspector – older driver (60+) SUV type vehicle Cutoff headlamps
(properly aimed)
Consistent parameters
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Visual nighttime inspections
Method advantages: Low administrative and fiscal burden Signs are viewed in their natural surroundings Low level of sign replacement and sign waste
Method disadvantages: Subjective … but research has shown that trained
observers can reasonably and repeatedly detect signs with marginal retroreflectivity.
Exposure/risk of conducting nighttime inspections Paying overtime
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The methodsVisual Nighttime Inspection
Calibration Signs Comparison Panels Consistent
Parameters Measured Sign Retro
Expected Sign LifeBlanket ReplacementControl SignsFuture Method Based On Engineering StudyCombination Of Any
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Measured sign retroreflectivityUse a portable instrumentReceive proper trainingHave a protocol for consistencyCompare readings to minimum values
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Measured sign retroreflectivityAdvantages:
Provides the most direct means of monitoring the maintained retroreflectivity levels
Removes subjectivityDisadvantages:
Cost of instruments (approx $10,000 to $12,000) Measuring all signs in a jurisdiction can be time
consuming Using retroreflectivity as the only indicator of whether or
not a sign should be replaced may end up neglecting other attributes of the sign's overall appearance.
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The methodsVisual Nighttime Inspection
Calibration Signs Comparison Panels Consistent
Parameters Measured Sign Retro
Expected Sign LifeBlanket ReplacementControl SignsFuture Method Based On Engineering StudyCombination Of Any
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Expected sign lifeFind the life of the sheeting type in your areaReplacement based on expected life for individual signs
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Expected sign life•Build and use a weathering rack like the one shown•AASHTO-NTPEP data•Sheeting company warranty information•Specify sign life•Measure existing signs with known install date and compare to min level
•Use weathering data or nearby jurisdiction’s weathering data
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Blanket replacementAll signs in an area/corridor are replaced at the same time at specified intervalsSpecified intervals could be set based on expected sign lifeSome existing blanket sign replacement policies exist using 10-12 years for Beaded High-Intensity sheeting signs
City of Tempe, AZ Maintenance Zones
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Control signsSign life is estimated using a subset of signs representing an agency’s inventory.
Subset of signs constitutes the “control signs” Control signs can be in-service signs or signs in a maintenance yard.Agency monitors control signs to estimate condition of all their signs.Periodically measure retroreflectivity of control signs.
Example of Control Signs
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Other options
Flexibility is provided for future advancements in technology and methods that have not been fully developed (must be based on an engineering study)Combination of methods, also
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The methodsVisual Nighttime Inspection
Calibration Signs Comparison Panels Consistent
Parameters Measured Sign Retro
Expected Sign LifeBlanket ReplacementControl Signs
Future Method Based On Engineering Study
Combination Of Any
What should you be doing now?Begin/update sign inventoryConsider which maintenance/management method(s) best for your agency (at least for now)Develop an SOP, policy memo, ordinance, etc. to establish the method(s) you will useTraining for you and staff/colleaguesBegin preparing budget authorities
Why take all this seriously?Will there be a federal or state Sign Inspector coming around? Don’t believe so.Must federally funded projects comply? Yep.Can this make a big difference in traffic safety for your residents and visitors? You bet.Will this be fodder for plaintiff’s lawyers, both legitimately and illegitimately? Most likely.
Why take all this seriously?Because it matters
Why take all this seriously?Because it matters
Why take all this seriously?Because it matters
Why take all this seriously?Because it matters
Why take all this seriously?Because it matters
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Need more info or training?Contact your local LTAP or T2 Center and/or your local FHWA division office
Typical workshop training available Overview Workshop Inspector Workshop
Delaware T2 Center Matt Carter, T2 Engineer
[email protected]; (302) 831-7236