I'm an American who lived in the UK for a couple of years. They have many roundabouts there, and I love them. But now I live in an American town with a few, and I've realized that there's a reason that they are less safe in the US than in the UK--besides the fact that American drivers are less familiar with them. It's a solvable problem, but not one I've heard people talk about. (Though to be clear, I'm not a traffic engineer.)
Most American drivers are familiar with slip lanes, which allow drivers to make a right-hand turns without necessarily coming to a stop. (Wikipedia article: https://en.wikipedia.org/wiki/Slip_lane. Note that the diagram shows an example from a country where they drive on the left side of the road.) They're convenient for drivers, but dangerous for anyone on foot or a bike. This is because a driver in a slip lane is looking for an opening in traffic in the direction opposite of the direction they're traveling.
A roundabout is basically an intersection made up of nothing but slip lanes. So they're fundamentally dangerous to pedestrians in the same way that a slip lane is, but the fact that vehicles are moving slower means that they're still safer than typical American intersections.
However, if I remember correctly (it's been over 20 years ago), in the UK they don't mix roundabouts and crosswalks. They'd put crosswalks (called "Zebra crossings": https://en.wikipedia.org/wiki/Zebra_crossing) between intersections, where drivers aren't distracted by other things. I think we need to do that in the US as well if we're going to adopt roundabouts.
In the Netherlands it is very common to have both crosswalks and bike priority lanes on the roundabout, especially in busy city environments. This actually improves safety, as the 'vulnerable' road users cross when drivers are driving slow and alert. Also, the access to the roundabout is slowed down by the crosswalks and bike lane, which improves safety for the drivers as well.
Note that it does require the design of the roundabout to be made with this in mind. Leaving any dutch roundabout involves a fairly tight 90 degree curve, forcing cars to slow down before encountering cyclists or pedestrians.
Roundabouts are also common in Australia, and crosswalks are placed some distance from them.
However, in my experience, pedestrians still cross at them all the time because an intersection (whether it's a roundabout, red lights, etc.) is always going to be the most convenient place to cross if you are trying to walk down a road for several blocks.
I have been living in a rural area of Australia now for over 10 years, and while I do think roundabouts are great, they should not be used where there are a lot of pedestrians. They get WAY overused in small rural towns here, leading to a high rate of rural pedestrian deaths.
Anecdotally, I also think the way roundabouts get built in the US is better now than a decade or two ago. It used to be that roundabouts (being unfamiliar) were just treated as a cookie-cutter object to plunk into the roadspace blindly.
Nowadays I often see the designers making conscious decisions like:
* what radius?
* what angle do we need so it doesn't even make sense to try to turn left?
* hard curb or drivable curb?
* central pit, flat center, or raised center?
* full roundabout, or teardrop-shaped (common on both sides of a highway bridge)? Apparently peanut-shaped is also a possibility though I haven't seen one.
* one-lane, two-lane, or a mixture (potentially including partial three-lane) depending on what part of the circle (common when there's a "major" road meeting a minor one)?
This is all of course ignoring the fact that drivers are also more aware of how to use them nowadays.
Americans still can't understand the passing lane. I'm skeptical that they're going to make effective use of roundabouts (although I do believe in their merits).
I fully believe that roundabouts work because they look dangerous and they force people to pay attention. There are other traffic management techniques that are overt about this inequality; you can design highways so it looks like you'll run into things you couldn't possibly hit and thus you slow down.
If left to voting instead of public policy, we will pick "feels safe but isn't" over "doesn't feel safe but is" which is why someone has to put their big boy pants on and build them anyway.
The data cited in the article is based on usage by American drivers. So you can drop your skepticism, they already work.
Anecdotally, they’re converting a number of intersections here in rural, Northern MN to roundabouts and they are _very_ effective at reducing fatalities and injuries.
I guess that depends on your definition of "work." Do they reduce delays? I believe (and have seen) that they can. But I've also seen traffic circles implemented with stop signs in the U.S., a failure.
But hey, I'm down for more to be built in the USA and let's give it a shot.
This is the reason on that traffic related infrastructure is so insane in the US: here we have evidence that roundabouts save lives, but the only thing the American can wonder is how fast they can get through it (to work no doubt).
I spend a lot of time near Manchester, VT where there are a handful of roundabouts including two in quick succession, one of which is as small as it is busy. The problem, based on my observations, is that many Americans have no idea how to use roundabout, nor how to signal through them. I feel unsafe every time I'm in the roundabout and have nearly been T-boned multiple times by people feeling they have the right to enter the roundabout regardless of existing motorists already being there. The Yield sign before the roundabout is ignored.
Also, require roundabout knowledge to pass the knowledge test to obtain a driver’s license, as well as practical experience when in a trainer’s permit. This ensures go forward expertise inherent in the population after a certain date.
People (education), process (implementation plan), technology (implementation).
It's possible, I haven't taken a driver's ed course in decades. Suggestions on potential data sources to confirm ground truth wrt this being included in current assessments?
> people feeling they have the right to enter the roundabout regardless of existing motorists already being there.
This baffles me. It's not like T-boning someone is good for your car either.
Only thing I can imagine is they think it will operate like getting on a freeway, where you have some time in a dedicated lane before you have to merge?
I live in the UK where roundabouts are ubiquitous and most people still don't understand them perfectly. The Highway Code[1] is too ambiguous.
- give priority to traffic approaching from your right, unless directed otherwise by signs, road markings or traffic lights
- watch out for all other road users already on the roundabout; be aware they may not be signalling correctly or at all
The second rule means if you have already entered the roundabout you have right of way over traffic yet to enter the roundabout to your right. What can happen in practice is that people to your right rock on and beep you out for the temerity of getting there first.
In the UK, roads entering the roundabout are often curved sharply towards direction of the traffic on the roundabout, so that it's more like merging lanes than entering a junction, so collisions are more likely to be sides hitting sides than a t-bone.
In rural America, there are super dangerous 4-way intersections with stop signs. We're talking highways with 55+ MPH (~88 KPH) speed limits that are relying on everyone to see the sign and stop. Roundabouts would be much safer and better for traffic flow.
There was a recent event where the interstate was closed (accident or something) and everyone had to re-route on those highways resulting in chaos at those intersections.
They are making these conversions at high fatality/injury intersections on rural highways here in Northern MN (our county is the size of the state of Delaware with a population of only 40k) and they are doing a great job at improving safety.
Trying to explain how roundabouts work to someone who doesn't get them is extremely frustrating. The rules are simple, but for some reason a lot of folks are vastly overthinking it.
The thing is, I like roundabouts, but I'm somehow not surprised that the metrics focus on accidents involving death or injury. I think that because people have to slow down, it must improve those metrics. But there's a particular glut of bone-headed people who power right into the roundabout without anything resembling yielding, to the point where I would legitimately not be surprised if there were actually more accidents overall. That may still be better, but it's incredibly frustrating how badly people handle roundabouts given their simplicity.
> But there's a particular glut of bone-headed people who power right into the roundabout without anything resembling yielding
Near my house are roundabouts that I have to drive in all the time. My number of near-collisions from people barreling through is ridiculous. Now if I'm in the roundabout I lay on my horn if I see cars approaching because they just don't pay attention.
It's sad they're so dangerous because of oblivious idiots. Those intersections are so much more efficient as roundabouts than if they were traditional four way stops.
> Trying to explain how roundabouts work to someone who doesn't get them is extremely frustrating. The rules are simple, but for some reason a lot of folks are vastly overthinking it.
It is a skill, it requires some practice. It's similar to math in that regards. And once you learn it you'd love them.
U.S. drivers are profoundly ignorant, and often belligerently so. They block the passing lane (this is the biggest problem in U.S. transportation, no exaggeration). They don't signal. They can barely park.
And most of all, they're texting ALL THE TIME. They kill pedestrians, kill other drivers, and steal thousands if not millions of hours from the rest of us every day. This is actively abetted by politicians, who refuse to impose any significant penalties for texting while driving. It should be a DUI-level offense, with the same penalties... ruthlessly enforced.
I have written to my state senators more than once about this issue... to no response at all. None.
I can't recall the last time I saw someone in the passing lane that was driving under the speed limit (or prevailing speed when there's traffic) except when preparing to turn left.
The passing lane has nothing to do with the speed limit. It's for passing only, at ANY speed (with the unfortunate exception of truly bumper-to-bumper traffic). When you're done passing (or aren't passing), GTFO. That's especially true if someone comes up behind you.
Some states have laws saying so. Illinois law says it's illegal to block the passing lane for more than half a mile at ANY speed.
Now states need to take the next step and paint "passing only" in the left lane. We spend trillions on highways, and then let one jagoff waste it all by blocking traffic.
Ah. In my state, California, the passing lane rule only applies if you're not already going the speed limit or if there is traffic congestion, the normal speed of traffic. If you're going the speed limit, you are under no obligation to get out of the left lane just because someone behind you wants to speed. Regardless though you're supposed to move right if you're moving slower than the lane to your right.
It appears that Illinois law also has an exception for traffic congestion, but not for speed limits.
I don't know if it is or isn't part of the exam to get a license, but even if it is licenses are more or less good for life once you have them, so you're looking at decades before everyone on the road would have to have passed that portion of the exam.
> I would legitimately not be surprised if there were actually more accidents overall.
That's possible, but people causing frequent fender-benders pay dearly for the privilege, so there's at least non-lethal feedback forcing them to improve.
Most people who object to roundabouts are drivers who don't know how to drive on them, which leads to hand-wavy dismissals of all criticisms of roundabouts as "you'll learn, look at these stats, they're safer!"
But for a pedestrian in a populated area, roundabouts are not an improvement.
Quick, how does a pedestrian safely cross a lane of traffic? Is it while dodging moving traffic, or does it involve traffic coming to a stop?
If you said the first, I hereby revoke your license to design public infrastructure. For pedestrians to safely cross a lane of traffic, cars need to come a stop, period.
And the whole selling point of a roundabout is that cars don't come to a stop. This is fine for rural areas or large interchanges. But for anywhere that pedestrians are expected to be, roundabouts make the environment more hostile.
And this is before we consider that to cross a roundabout requires setting the pedestrian crossings back from the intersection, forcing pedestrians to zig-zag in order to use them.
And this is also before we consider that we know for a fact that shallower turns (which allow cars to retain more speed) are less safe than sharper turns (which require cars to shed speed), which further exacerbates the pedestrian safety issue.
To say nothing of the fact that roundabouts preclude implementing pedestrian scrambles, which are the safest and most efficient form of pedestrian crossing.
Roundabouts are a solution to a problem of making roads safer for cars, at the expense of pedestrians and cyclists. They exacerbate the problem of our depressingly car-oriented infrastructure. "But the stats say they're safer!" Yeah, and when Google reduced page sizes they saw their average latencies increase. This is a fun way of lying with statistics. Sure, fatalities from roundabouts go down when you create such a human-hostile environment that every pedestrian and cyclist goes out of their way to avoid it, or just throws their hands up in despair and buys a car, since it's a signal that car owners are the only thing people worth optimizing for.
I'd rather cross at a roundabout than at a crosswalk somewhere along a straight road. Actually, last week I got almost run over in such a situation. A bus stopped for the crosswalk, blinked lights to indicate he'd seen me. I start to cross, and at the same time a van overtakes the bus at 'normal' speed and almost running me over as I could not see the van behind the bus, and the van could not see me. This would not have been possible at a roundabout as all traffic is slow and overtaking is not possible.
Having looked at some of the links in the article, I just realized that one extra feature of roundabouts is that they allow U-turns (which is not always the case at an intersection).
"As a person with a vehicle built within the past 15 years with massive A-pillars, I don't like them."
I'm actually fond of rotaries in general. But especially for newer smaller ones, it feels like the gradual turning of your path is much worse for keeping a walking pedestrian within your recently-created front blind spot as you're merging in, just when your attention is focused on other cars. I counter by bobbing my head left and right to see around the post, but I don't think most drivers do this.
I obviously can't argue with the statistics, but I also have to wonder if they're telling the whole story.
No HN discussion of roundabouts is complete until someone has posted the Magic Roundabout. There are several in the UK, this is the one nearest to me. And yes it's as insane to drive on as it looks, but safer as everyone is terrified and drives slowly. https://en.wikipedia.org/wiki/Magic_Roundabout_(Hemel_Hempst...
Road Guy Rob did a video a little while ago, "Let's FIX the HIGH SCHOOL... with 152 ROUNDABOUTS!":
> When the bell rings at Carmel High School, parents race in from all directions to create a zoo of cars, students, and tired teachers all try to use the road at the same time. How a city's failed attempt to build two roundabouts to fix the problem led to an addition.
> Red lights ruin perfectly good highways and make them grow wider than they really need to be. How a town got a highway moving fast again without adding a single new lane.
I live in a country where roundabouts are common. They're great for relatively low traffic intersections as you can often get through much faster than lights.
They are a liability when traffic levels are high enough - say during peak times - when one inbound direction is blocked by another.
I don’t think Americans loathe roundabouts. They’re just unfamiliar. So when someone says “would you like to add an unfamiliar section of road design in our town?” most say no.
> They are a liability when traffic levels are high enough - say during peak times - when one inbound direction is blocked by another.
The rule should be that when traffic is bumper to bumper, the "zip" is made mandatory. That rule already supersedes the normal rule on, say, many (all?) european highways when the highway goes from, say, 3 lanes to 2 lanes and in case that creates a traffic jam: people in "their" lane doesn't have the right of way anymore. It's one car from one lane, one car from another lane: the "zip".
People in a roundabout should lose their right of way when traffic is bumper to bumper.
Where I live people are extremely polite on the road so I don't even know if the zip it's mandatory: people shall simply act that way.
In countries where road rage is common and people misbehave, like France, just make it mandatory by law.
The zip does nothing on the roundabout.
bumper to bumper is very-rare, and it mostly happens momentarily due to pedestrian crossings placed directly after the entrance/exit of the roundabout.
What is actually super dangerous are the non-standard 2/3 lane roundabouts where the first lane gets "ejected" at the next/second exit forcibly, while the 2nd lane can either exit or continue on the roundabout, so many lorries in the 1st lane try to runover those in the 2nd lane trying to exit.
I'm in France and we do Zip in my area (which is quite touristic and see huge traffic right now, so I do that quite often when I drive in summer). But it is true that around Paris and in southeast France, people usually misbehave and act like entitled pricks.
Multi-lane roundabouts, though, freak me out when they're really tight, have a lot of lanes or don't have lane markers (e.g. Place Charles de Gaulle in Paris).
I didn't get from the article: are they better than all traffic signals, or signals with unprotected left turns? And what's a good vs. bad turnabout like?
I have had to go through a few that feel extremely dangerous compared to having all cars stop for me. So I know I must be missing something.
Edit: Also, I see a lot of comments on yield. I'm probably confused too, but how do they work when traffic is non-stop? Is there a specific traffic rate beyond which roundabouts become less safe?
The thing is that a “yield” is not a “stop”, you have to match your pace to the circulating vehicles, similar as a highway “on-ramp” you don’t stop to let all the cars pass or slow down, that’s worst than speeding up and finding your space in traffic.
In California at least, the rules for entering a roundabout are to slow down when approaching, yield and prepare to stop to traffic in the roundabout and continue when there's a big enough gap in traffic to merge safely.
While in a roundabout, there's no passing permitted so you're essentially moving at the slowest vehicle's speed (which can be you). This rule can cause a problem if you're in the inner lane or a multilane roundabout and want to exit when a car is to your right when people don't choose their lanes properly when entering.
Highway merges have somewhat different rules in that you must be at or near the speed of traffic when merging instead of slowing down and you're not permitted to stop unless absolutely necessary.
Carmel, Indiana has over 150 roundabouts and they are building more. I believe we have less than 5 traffic light intersections now but I'm not 100% sure.
The movement around Carmel is remarkable compared to driving next cities (Indy, Fishers, etc). Fishers and Westfield are building more roundabouts as well.
As for one person who commented about high traffic locations - Carmel would make an overpass for those intersections though they are not many.
They intend to replace the last 14 of 15 traffic signals remaining with roundabouts, leaving the last one (located at Main and Range Line) for historical purposes, as it was the first in the state and one of the first in the country.
As an American, I don’t see a ton of these - but they are absolutely more efficient at intersections without a ton of traffic. The length of red lights can be ridiculous in places where you just sit and wait with no traffic.
I'll like roundabouts as soon as someone comes up with a good way to fix the resource starvation problem (i.e., if there's a constant stream of traffic from your left, you'll never get a turn to go).
Roundabout’s are only suitable for intersections where traffic on each route is roughly equal. In NZ I can’t recall seeing roundabouts built where the routes are not roughly equal in size and volume. In saying that, mistakes happen and things change and there are roundabouts that suffer this sometimes.
> I'll like roundabouts as soon as someone comes up with a good way to fix the resource starvation problem (i.e., if there's a constant stream of traffic from your left, you'll never get a turn to go).
> Doesn't that give up a lot of the benefits of having a roundabout at all, as opposed to having a regular signal-controlled intersection?
If congestion occurs only at "peak" time(s) (e.g., rush hour(s)) then that's when you are stop/go with signals, whereas the rest of the time the signals are set to the 'traditional' roundabout way (perhaps flashing yellow?), then it could still mean that for (say) 20 hours of the day you still have the benefits (plus also during weekends).
And even during peak time(s) you probably get reduced collision rates and collision intensities.
Most American drivers are familiar with slip lanes, which allow drivers to make a right-hand turns without necessarily coming to a stop. (Wikipedia article: https://en.wikipedia.org/wiki/Slip_lane. Note that the diagram shows an example from a country where they drive on the left side of the road.) They're convenient for drivers, but dangerous for anyone on foot or a bike. This is because a driver in a slip lane is looking for an opening in traffic in the direction opposite of the direction they're traveling.
A roundabout is basically an intersection made up of nothing but slip lanes. So they're fundamentally dangerous to pedestrians in the same way that a slip lane is, but the fact that vehicles are moving slower means that they're still safer than typical American intersections.
However, if I remember correctly (it's been over 20 years ago), in the UK they don't mix roundabouts and crosswalks. They'd put crosswalks (called "Zebra crossings": https://en.wikipedia.org/wiki/Zebra_crossing) between intersections, where drivers aren't distracted by other things. I think we need to do that in the US as well if we're going to adopt roundabouts.