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Feds, Advocates Talk About What’s In The New MUTCD (And What Isn’t)!

The new MUTCD isn't the revolutionary rethink advocates were asking for, but it does offer transportation officials more flexibility to design roads safely. The only question is whether they'll take it — or stick to the status quo.

6:44 PM EST on December 19, 2023

Photo: Josh Katz|

The new Manual on Uniform Traffic Control Devices is out!

Eighty-six the 85th!

The long-awaited revision of the Manual on Uniform Traffic Control Devices gives engineers new flexibility to design streets for safety, including downplaying the hated "85th percentile rule" for setting speed limits — but some advocates fear that engineers won't take full advantage of it without more transformational changes.

On Tuesday, the Federal Highway Administration finally published the 11th edition of what's come to be known as the "notorious MUTCD," marking the first time since 2009 that the agency has updated its official guidance on how to safely utilize the signs, signals and markings that annotate U.S. roads. In the intervening years, U.S. road deaths have shot up 26 percent, with pedestrians and fatalities skyrocketing 82 percent over the same period.

The new revision was conducted, in part, in response to a massive national advocacy campaign which, according to the FHWA, flooded the agency's offices with more than 100,000 comments — many of which came from safe streets advocates concerned that the document encouraged cities to put dangerously high numbers on speed limit signs while putting up too many roadblocks to installing crosswalk, bike lanes and bus lanes.

In a notice of proposed amendments that accompanied the revisions, the agency addressed — and, frankly, dismissed — many of those concerns, while stressing, curiously, that "the MUTCD is not a roadway design manual, nor is it a comprehensive safety manual."

"Nothing in [it] restricts a community from designing walkable, transit-oriented roadways or high-speed highways as that community determines appropriate to serve its needs." (Emphasis ours.)

Still, agency officials hope that, on balance, the new Manual will give engineers the freedom and guidance they need to choose the former rather than doing what they've always done (the latter) in the misguided notion that all that matters is vehicle throughput.

In an interview with Streetsblog, Federal Highway Administrator Shailen Bhatt reiterated that the MUTCD is just a guidebook — one that he hopes cities will use to make improvements.

Federal Highway Administration Administrator Shailen BhattPhoto: International Transport Forum

"The cities that are really thriving in the 21st century are the ones who are really putting active transportation at the forefront of their transportation solutions," said Bhatt, a Biden Administration hire. "What I think we've done with this MUTCD, and what we'll continue to do with future iterations, is give people the tools to make that the foundation."

Advocates, though, say that foundation could stand to be a lot stronger.

"It’s a transitional document; it’s not at transformational document," said Mike McGinn, executive director of American Walks. "It’s still anchored in the prior MUTCD, and how far they were willing to keep moving was limited by that." 

Advocates are still digging through the 1,114-page document (and its side-by-side with the previous version), but several analysts have pointed out a few bright spots in the tome — and a few dim ones.

Good news

On the positive side, the new Manual clarifies that roads should be designed with the understanding that humans make mistakes, rather than "reasonable and prudent" drivers motoring amidst "alert and attentive" pedestrians who universally understand local laws. The text also has doubled the guidance on allowable bike signs, signals and markings and eased the process to install certain types of walking and transit infrastructure, like red pavement markings on bus lanes and pedestrian-activated signal beacons at crosswalks.

Less good news

Advocates expressed mixed emotions, though, about the Manual's updates to the 85th percentile method of setting speed limits, which has long advised transportation officials to base them on the top velocity that drivers naturally travel when there's no congestion on the roads, after excluding the 15 percent of motorists who drive the fastest and cause the most crashes. First proposed based on the findings of a 1964 safety study conducted on rural highways with few pedestrians or sidewalks, the concept has become a rule of thumb for speed limit setting even in urban areas — and even when the speeds the formula spits out are far above the 20-mile-per-hour threshold at which crashes become far more lethal to people who walk.

The new Manual, by contrast, emphasizes more strongly that the 85th percentile "rule," as its colloquially known among engineers, has never been a federal law at all, and that it's just one of several factors roadway designers should consider when setting limits — particularly in "urban and suburban arterials and rural main streets" where people and cars tend to mix. The notice of proposed amendments also teases that the FHWA is in the process of developing "a comprehensive guide for speed limit setting" that could someday remove the issue from the pages of the MUTCD entirely, besides basic guidelines about how signs should visually look.

"We're not designing and building roads the way we did in the 1950s and '60s," added Bhatt. "We've changed our approach from moving cars and trucks to moving people. ... We're very clear in this new update that the 85th percentile should not be used as the sole consideration in setting speed limits. We want people to take in factors such as areas with pedestrians, bicyclists, other road users, and other characteristics of the roadway, and not just defer to the highest speed that a percentage of the people might be driving."

Some advocates say, though, that the Administration is naive to believe that engineers will consider factors other than 85th percentile speeds — especially without clear guidelines telling them exactly how to set safer limits instead. And that's in part because, however much the FHWA says that the Manual of Uniform Traffic Control Devices "is not a road design manual" that carries the force of law, overworked engineers fearful of lawsuits certainly treat it that way, even when the text gives them nominal permission to consider options besides the status quo.

"Unfortunately, I find that [the FHWA] fails to recognize its own authority and power," said Beth Osborne, director of Transportation for America. "They may not mean for something they publish to have such wide-reaching effects, but it does. ... Transportation officials treat the MUTCD as cover for liability; [they think] as long as you adhere to it, you’re covered. And courts treat it that way, too."

Of course, advocates will have another opportunity to address the shortcomings of the 11th MUTCD pretty soon. Under the Bipartisan Infrastructure Law, the Manual is required to undergo an update every four years, which Osborne says could give the agency the opportunity to integrate guidelines from other countries with lower roadway death rates, as well as giving newer, Vision Zero-minded voices a seat at the drafting table.

"We should be looking at existing standards skeptically, because they’re not giving us the results we really want," Osborne added. "I don’t get the sense that the current edition is doing that."

For his part, Bhatt acknowledged that "we have not solved every challenge that was raised 100,000 comments that came in," but added that "that it won't be another 15 years before we get a new update."

And whenever that process begins, advocates will be ready — because they saw that their voices made a difference this time around, however mild those changes may have been.

"It’s a better update than it would have been if people hadn’t spoken up," added McGinn. "I think the most important thing now, is just demanding that your local leadership deliver good streets. They’ll have more room to do so within this manual than they had before. But if we don’t speak up, it won’t happen."

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