Remember back in our February 2021 e-newsletter we talked about the proposed rulemaking for the 11th Edition of the Manual on Uniform Traffic Control Devices (MUTCD)? Well, that’s not what this article is about, because we’re still waiting on that to wrap up. But we did get to see the Final Rulemaking in the Federal Register for quantitative retroreflectivity standards for pavement markings.
Take a look at the Federal Register yourself, but unless you enjoy a lot of “he said this and she felt this other thing but we decided to go another way” kind of stuff, skip down to page 8 for the actual wording that is now incorporated into the MUTCD and has an effective date of September 6, 2022. We’ll summarize it here, but don’t cheat – at least go read the page or two that actually has the new language. There could be a quiz.
First, let’s be clear. Existing language for some time has said that, “markings that must be visible at night shall be retroreflective unless ambient illumination assures that the markings are adequately visible.” (MUTCD, Section 3A.02) This is what some would call a qualitative standard, because it is not specific as to how retroreflective. The new rulemaking carries quantitative definition, at least for some pavement markings.
Now in the rulemaking, there are some exceptions, but these are exceptions to the quantitative minimum levels for retroreflectivity – the qualitative requirement that all markings shall be retroreflective applies to all markings that must be visible at night. The quantitative (numeric) standards in the rulemaking do not apply to roadways with speed limits less than 35 mph or roadways with average daily traffic (ADT) less than 6,000 vehicles per day. So, many municipal streets are not covered by this quantitative standard. In addition, non-longitudinal pavement markings, such as stop and yield lines, words, symbols, arrows, and crosswalks are not covered by these quantitative standards.
But if these markings must be visible at night in order to be effective, they shall be retroreflective or illuminated; we just can’t tell you how retroreflective. Is your best bet to pretend your markings are covered by the standards? Not to be weasels about it, but that’s a risk assessment decision your agency has to make. But, yeah, we think leaning in that direction is a good idea from a liability point of view and, more importantly, for the protection of road users in your jurisdiction, which is the game we actually signed up for.
Markings that you can choose to exclude from the quantitative standards include curb markings, parking space marks, shared-use path markings, and those dotted extension lines that extend longitudinally through an intersection, major driveway, or interchange area.
What’s left? Longitudinal lines on roadways with posted speed limits of ≥35 mph and at least 6,000 ADT. For those markings (took six paragraphs to get to the point…sheesh) agencies shall use a method designed to maintain retroreflectivity under dry conditions at or above 50 mcd/m2/lx. That is the standard and you’ll notice it has some similarities to the sign retroreflectivity (MUTCD Section 2A.07) language, in that the standard is that you must have a method in place and if you are diligently applying it, there are some support statements that provide latitude if special circumstances arise (isolated degradation, snow plowing, equipment issues, etc.). Again, scroll to page 8 in the rulemaking and have a look yourself.
In addition to the standard, guidance is included for roadways with speed limits ≥70 mph, in which case, the dry condition retroreflectivity should be at or above 100 mcd/m2/lx. Most of us aren’t dealing with those roads, so we won’t dwell on that.
But we do love to dwell.
Some of you aren’t used to these new units, so let’s just pause a moment for the definitions in the sidebar over here. So then, a millicandela per square meter per lux, mcd/m2/lx, is just a light intensity thing. Don’t sweat it – it’s just the units that the instrument reads out, you’re not going to have to do unit conversion mathematics, and it’s not going to be on the quiz.
Which brings us to the question of how we comply. Not unlike sign retroreflectivity, the Federal Highway Administration gives us some choices, and they are laid out in a companion document, “Methods for Maintaining Pavement Marking Retroreflectivity.” These include direct measurement with an instrument similar to the one used for signs, but also includes nighttime visual inspections, expected service life, and blanket replacement.
For those of you with linework where these quantitative minimum levels apply, the standard provides for a pretty reasonable compliance date (i.e., having a method in place) of four years from the effective date, meaning your method must be in place by September 6, 2026 and there’s already a handful of you counting on your fingers to see if you’ll be retired by then. Stop it.
Now briefly back to the 11th Edition rulemaking (first notice dating back to December 2020), which promises to bring a whole lot of new, less dramatic changes to the MUTCD. The Infrastructure Investment and Jobs Act (aka, the Bipartisan Infrastructure Law, the IIJA, the BIL) requires the Federal Highway Administration to update the MUTCD no later than May 15, 2023, so you can be sure you’ll see an article on that from us before then.
The Delaware T2/LTAP Center’s Municipal Engineering Circuit Rider is intended to provide technical assistance and training to local agencies and so if you have MUTCD questions or other transportation issues, contact Matt Carter at matheu@udel.edu or (302) 831-7236.
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