We do want to stop traffic deaths, but we don't want to change anything that would stop traffic deaths
Modern roundabouts are the safest form of at-grade intersection. If you take traffic safety seriously, stop shrugging off intersection design.
“Slow and low—that is the tempo.” Beastie Boys, on the benefits of traffic calming
Your state department of transportation says safety is their top priority. Your city or county administration says the same thing. Isn’t that what “public service” is all about? Mayors, council members, planning commissioners, city planners—there’s a large group of people who show up on the evening news grief stricken about the latest fatal crash. I do believe they sincerely mourn these tragedies, especially when pedestrians or bicyclists are killed.
Life is full of risks. According to the CDC, the bathroom is more dangerous than bike lanes. Those of us who’ve had young kids take preventative measures like using one of those sticky rubber mats inside the tub, and a floor mat that doesn’t easily slide. We take note of what’s causing harm and act on it.
For harms that might not be so obvious to us, we adapt based on insights from subject matter experts. There was a time when homeowners had no idea lead paint was a potential hazard. Now, any house built before 1978 gets tested for it. I’m sure you could list a bunch of social norms that abruptly changed once a clearly safer alternative became widely available.
Transportation professionals have a safe alternative for intersection design, but refuse to use it.
Modern roundabouts are the safest form of at-grade intersection.
Transportation safety researchers have a grade-separated category when they study crashes and design features. That makes sense, because driving on interstates with on-ramps and off-ramps is very different from a surface street with driveways and cross-streets on the same grade.
And when it comes to all the types of at-grade intersections, roundabouts are by far the safest. It’s crazy how controversial that statement is, given the Federal Highway Administration has been documenting safety statistics for decades. They even have a dedicated webpage to proven safety countermeasures. How often does any authority in any industry use the word “proven”? Not often! And of course experts don’t toss around “proven” lightly because we’re such a litigious society.
Here’s what the U.S. Department of Transportation says (emphasis mine):
The modern roundabout is an intersection with a circular configuration that safely and efficiently moves traffic. Roundabouts feature channelized, curved approaches that reduce vehicle speed, entry yield control that gives right-of-way to circulating traffic, and counterclockwise flow around a central island that minimizes conflict points. The net result of lower speeds and reduced conflicts at roundabouts is an environment where crashes that cause injury or fatality are substantially reduced.
It’s not complicated. Roundabouts slow down car traffic, and there are fewer points in the intersection where cars, bicyclists, or pedestrians interact with each other.
A four-legged intersection has 32 vehicle-to-vehicle conflict points and 24 vehicle-to-pedestrian conflict points. A four-legged roundabout has only eight vehicle-to-vehicle conflict points and eight vehicle-to-pedestrian conflict points. Roundabouts remove the dreaded t-bone crash that will always exist at standard four-legged intersections.
(And of course, the wider the intersection, the more conflict points appear. That’s partly why 6-lane arterials are so dangerous.)
I don't think traffic engineers are even aware of the Insurance Institute for Highway Safety’s work on this issue. They say "roundabouts are a safer alternative to traffic signals and stop signs." You know an insurance organization won’t be reckless with the word “safer.”
There's no question if DOTs can save lives immediately by replacing signals w/ roundabouts. The only question is how many.
In some places, fatal crashes are completely eliminated. Carmel, IN has become the roundabout capital of the world because of its 140+ roundabouts around the city. It’s not a public arts campaign, it’s a direct response to crashes. The more signals they replaced with roundabouts, the more they reduced the number of crashes, injuries, and fatalities.
United States average fatality rate: 14 deaths per 100,000 per year
Carmel average fatality rate over last five years: 2 deaths per 100,000 per year
Here's a New York State DOT study that estimated 51,000 crashes could have been prevented in a single year if only 10% of signals were roundabouts. Mind blown, right? That estimate included 231 deaths and 31,000 crashes with injuries. Traffic engineers should be clamoring for design change along with every traffic safety advocate.
Stop asking voters if saving lives is good policy. People are illogical creatures who routinely make choices that go against their own personal interests.
Here’s a typical response to traffic calming projects like road diets with roundabouts:
Local governments have a reputation for kicking off a project by saying, "We're going to choose the most popular design option for this corridor. Please vote." And time after time, voters chose the option proven to increase crashes, increase injuries, and increase fatalities.
An accountant’s view of the death toll.
In the United States, one human life is valued at $10 million. Listen to this NPR interview if you’re curious how that came to be. Putting aside the social trauma and devastation of traffic deaths, consider the financial impact.
DOTs may run benefit/cost calculations for materials, equipment, and labor, but they aren’t showcasing a life-cycle cost that includes human life. DOTs waste millions every year by widening intersections instead of converting to roundabouts.
Roundabouts save lives. Lives are worth $10 million each.
Traffic signals cost lives. Lives cost $10 million each.
Maybe the path to vision zero is winning over the accountants. Everybody celebrates the hero who stops the financial hemorrhaging.
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