Retroreflectivity What is it and Why Should I Care?

RetroreflectivityWhat is it and Why Should I Care? Matheu J. Carter, P.E. T2 Engineer Delaware T2 Center October 15, 2009

Delaware T2 Center • T2 Centers or LTAPs located in all 50 states • Funded by FHWA and state DOTs • Mission – promote training, tech transfer, research implementation at local level • Delaware T2 hosted by University of Delaware, part of Delaware Center for Transportation

Matt Carter • Currently, Delaware T2 Engineer, Municipal Engineering Circuit Rider, Safety Circuit Rider • Professional Engineer, licensed in six states • 20+ year career, civil & env engineering • Bridge, road, utility construction • Design consulting • Public sector (Director, DPW, Cecil County, MD)

Outline • What 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?

Caution • This is a big topic • While a good start, this 2-hour webinar alone won’t prepare you • So 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 source • It is not mirror-reflectivity, which bounces light off in the opposite direction • It 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 travel • Applies to TCDs on “any street, highway, or bicycle trail open to public travel” – 23 CFR Part 655 Subpart F • Many states have their own MUTCD that meets or exceeds the federal manual

Origin of retroreflectivity standards • General retroreflectivity standards have existed in the MUTCD for some time – Section 2A.08 • 1993 DOT appropriations act required standards • Minimum retroreflective requirements established in Revision 2 of the 2003 Edition – Section 2A.09 • Minimum 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-3 • Sheeting 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)

Exempt signs • Parking/Standing/Stopping • Walking/Hitchhiking • Adopt-A-Highway • Blue or Brown Backgrounds • Exclusive Use of Bikes or Pedestrians Note: Must still meet other requirements 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, 2008 • 1st 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.

The methods • Visual Nighttime Inspection • Calibration Signs • Comparison Panels • Consistent Parameters • Measured Sign Retro • Expected Sign Life • Blanket Replacement • Control Signs • Future Method Based On Engineering Study • Combination Of Any

Visual nighttime inspection • Trained inspector • Visual inspection/assessment at night • Need to tie to minimum values by using • Calibration signs procedure, or • Comparison panels procedure, or • Consistent parameter procedure

Visual nighttime inspection • Common 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

Calibration signs You “calibrate” your eyes with calibration signs • Calibration signs are near minimum retro • You then evaluate signs as compared to calibration signs

Comparison panels • Tie to minimum values with comparison panels • Panels are near desired retro • Clipped to sign - viewed from distance • Evaluate signs compared to panels

Consistent parameters • Uses parameters consistent with those used to develop the minimum levels • Inspector – older driver (60+) • SUV type vehicle • Cutoff headlamps (properly aimed)

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

Measured sign retroreflectivity • Use a portable instrument • Receive proper training • Have a protocol for consistency • Compare readings to minimum values

Measured sign retroreflectivity • Advantages: • Provides the most direct means of monitoring the maintained retroreflectivity levels • Removes subjectivity • Disadvantages: • 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.

Expected sign life • Find the life of the sheeting type in your area • Replacement based on expected life for individual signs

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

City of Tempe, AZ Maintenance Zones Blanket replacement • All signs in an area/corridor are replaced at the same time at specified intervals • Specified intervals could be set based on expected sign life • Some existing blanket sign replacement policies exist using 10-12 years for Beaded High-Intensity sheeting signs

Control signs • Sign 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

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

What should you be doing now? • Begin/update sign inventory • Consider 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 use • Training for you and staff/colleagues • Begin 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

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 • matheu@udel.edu; (302) 831-7236

Retroreflectivity What is it and Why Should I Care?