It was a revelation when driving through the UK that driving could be enjoyable again. In light to moderate traffic, there was rarely a need to stop. In contrast, in the US, it's stop/go/stop/go. Even in heavy traffic, the roundabouts were better in terms of throughput and safety.
Roundabouts stop being useful once you get to "gridlock" style traffic, though. Because the traffic tends to work its way back into the roundabout and clog the whole thing up. I experienced that this spring in Scotland on a visit.
So long as the traffic flow is at least the double-digits (mph or kph) roundabouts are just fine. Below that though, and there be dragons.
People tend not to jam up intersections with stop signs unless there's a bit of space for them on the other side of the intersection. Same for stoplights, although there are some cases where traffic backs up into the intersection though that generally has more to do with people who are moving (albeit slowly) and then everyone jams on the brakes all at once, stranding several in the intersection.
I blame the stop/go/stop/go feeling of US driving more on the grid rather than the lack of roundabouts. 4-way intersections are relatively rare in the UK, most minor road intersections being T-junctions.
City planners are aware that continuous driving is enjoyable and go out of their way to eliminate that enjoyment wherever possible. It's called "traffic calming," though I'd argue the results are the exact opposite of calming.
Drivers who are comfortable, having fun, and moving continuously are much more likely to speed and get in accidents than drivers who are annoyed and constantly vigilant for conditions changing second-to-second (like stop-and-go traffic).
They missed out on the biggest problem with roundabouts: Their worst-case traffic behavior is cancerous. If any single exit is blocked, entry traffic will become blocked in all directions. And if the road grid is dominated by roundabouts, the problem grows in all directions.
It's not a problem when traffic is just congestion. It's hardly a common problem at all. But when it is a problem, such as is the case with a traffic accident that blocks multiple lanes of traffic, it causes full-stop gridlock to grow outward to the point of full paralysis.
The worst traffic jam I have ever been in was not in NYC, Boston, Seattle, or San Francisco, but rather in Idaho Falls, Idaho on a normally empty country road that was running parallel to the road where a drunk driver caused an accident that blocked the roadway. That single accident caused me and hundreds of other cars to sit in the same spot for almost 4 hours.
One more problem is pedestrian crossings. With a traditional intersection, only cars changing direction cross the path of the pedestrian. On a roundabout, when you cross one of the exit arms, your path is constantly crossed by drivers going straight through, doing a right turn, doing a left turn and doing a U-turn. They are all driving at full speed too, rather than just starting from a stop. It is a delicate game where you gently put your foot forward to signal your intent, wait for the incoming traffic to stop for a moment, then dash to the other side. This is generally my experience, but maybe in other places drivers treat pedestrians on zebras differently.
One some larger roundabouts in the UK (and no doubt other European countries), they have traffic lights on the roundabout, between exits (I'm not talking about the entry lights). If one exit is totally blocked, these lights can allow traffic to continue out of other exits.
This "biggest problem" also occurs with traditional intersections.
In both cases, traditional or roundabout, drivers are supposed to leave gaps in the traffic to at least let some cars through the intersection.
In both cases, if drivers don't follow that rule gridlock will ensue. In fact, 2-3 cars stuck in the middle of a traditional intersection is often all you need to completely block entry and exit traffic by preventing anyone from going straight or making left turns: https://en.wikipedia.org/wiki/Gridlock
> If any single exit is blocked, entry traffic will become blocked in all directions
Typically in the UK, if the traffic is this bad, then drivers on the roundabout leave gaps to enable cars going in uncongested directions to get through.
Denver has a handful of growing roundabouts in newer neighborhoods, but unfortunately they keep installing them in all the wrong places. I'm convinced they are "testing the waters" by placing them in residential neighborhoods with very little traffic, which honestly just makes people annoyed by them, rather then appreciate them.
Roundabouts aren't a replacement for stop signs, they are a replacement for stop lights.
Some of the most egregious roundabouts I've ran (heh) into have been in Aspen. They're right after you get off 70 (ie going 65/70 mph) and are often overgrown with bushes and trees. I'm all for roundabouts, I think when done right they're great, but I don't know what they were thinking when putting these in.
I remember when they installed one out in Littleton (suburban Denver) - it flows traffic spectacularly but it took years, maybe even a decade for people to get used to it.
I once came upon it and found a full size four door sedan in the (raised) island in the middle with four befuddled teenagers standing around shaking their heads. They had plowed into the traffic circle straight ahead, jumped the raised embankment and landed right in the center island.
Light traffic residential areas are a perfect place for them. There's nothing more annoying than observing a stop sign in an empty road. I have roundabout near me and when there is no traffic on the roundabout you just drive through it. The residential roundabouts have only a slightly raised centre so you can drive through in almost a straight line.
Late at night when there is no traffic it saves having to stop at all.
I think the exact opposite, that four-way stops should for the most part become roundabouts, and that's it. And actually, just four-way stops between two-lane roads, once you start adding lanes it gets too complicated.
In Spain, basically everything is a roundabout, so much so that when the roads are big enough they have lights within the roundabout. That's way too much IMO.
I live in Victoria, Australia, and we’ve had roundabouts for ages. I think they are very good for a certain scale of road/traffic. Mostly intersections with moderate amounts of traffic on average, and not high-speed. e.g., the main intersections within housing estates. Having too many of them instead of give-way signs drive you a little batty (I’m looking at you, Warrnambool) while really heavy traffic, major intersections work better with traffic lights.
My daughter recently got her learner license, and she has found roundabouts one of the trickier intersections to navigate. You have to read the traffic flow. This person about to enter on your right is going straight ahead, so will block you entering the roundabout[1], but they have to wait for that person coming the other way from you and going straight through, so you can slip in the gap that creates without cutting anyone else off. As with many things it is familiarity and practice that makes them work[2]. I think roundabouts work very well here for the most part, and my daughter is getting pretty good at reading the traffic. It’s not rocket science[3].
The science of roads and traffic I imagine is a surprisingly nuanced expertise involving a lot of physics and psychology. I find when I cross over the border to New South Wales I feel like a long-tailed cat in a room full of rocking chairs. I eventually figured out it was because the signage was a different distance before the intersection compared to my home state. Once I was aware I could adapt.
[1] We drive on the left side of the road because Australia is in the southern hemisphere.
[2] I bet the first traffic lights caused an uproar. “Why the hell should I stop just because there’s a red light?!”
I grew up in Australia in a town nicknamed "The city of roundabouts", I know a thing or two about them.
Upon moving to North America, it was shocking to encounter my first 4 way stop. To this day I still shake my head every time I encounter one.
They are non-existent in Australia.
It's been amusing watching the resistance of North Americas to roundabouts, I think, because they are never taught how to use them. Sometimes I ask people the correct way to signal in a roundabout, and I swear I've never had two people in the same room agree.
The city of Calgary installed one, and it was taken out soon after because of a public outcry.
In another city in North America I lived in, they put one in, and a lady promptly drove straight through it, crashing her car. She sued the city and one, because it wasn't fair to go and put in a roundabout like that.
One of the odd things about moving from Italy (where they've had them for a while) to Bend, Oregon is that there are actually a ton of roundabouts here in Bend, for whatever odd reason. People seem to handle them just fine.
There are two problems with roundabouts in America.
The first problem is the people who don't know how to drive. I cannot count the number of times I have seen people stop in the middle of a roundabout to let cars in, or stop at the entrance and stare in confusion when there is absolutely nothing coming.
The second problems is inherent in the design. A line of traffic that is going straight can, effectively, prevent any cross traffic from entering the roundabout, due to the small radius of most US traffic circles. This is a trade-off, of course, and is still safer than traffic lights or a 4-way stop, and usually more efficient.
I see the first problem all the time, especially at stoplights. Often when there is a line of cars waiting at a red light, when it turns green someone will remain stopped so that a waiting vehicle on a perpendicular street or nearby business can pull onto the highway in front of them.
They think they're being polite, but they're forcing dozens of cars to wait for an additional cycle of the stoplight, whereas if they had just pulled through the light as normal then the waiting car would get a chance to merge as traffic either cleared or came to a stop again.
Interesting observations. As a counterpoint, there are a couple of roundabouts between here (Phoenix) and Las Vegas, notable both because there's often fairly heavy traffic and that almost everyone on the road is from elsewhere (and therefore unfamiliar). They seem to operate quite smoothly, and are a welcome break from waiting for several cycles of traffic lights.
I'm curious... where have you seen these troubles? Perhaps the small radius is the real issue?
Simple educations campaigns would solve the driver education issue. Get all networks to run ads with celebrities showing how to drive in a roundabout. You could throw in some non-texting message while at it.
The ignorance argument is difficult to agree with because every country has had to introduce them to an uneducated population at some point. You could have used the same argument against traffic lights.
It seems that the slight inefficiencies you cite in the first complaint would eliminate the phenomenon described in the second complaint.
The point of roads is not to transport any particular traveler at the greatest possible speed, but rather to transport all of us in safe and convenient fashion.
The first problem is a problem with US drivers in general. I don't know what we should do about it, except perhaps test people's driving abilities more frequently. I, for one, honk at people who fuck up my roundabout experience.
I think the second problem is an acceptable tradeoff, but ymmv
There are a couple of roundabouts where I live, and I see the second problem all the time. The best (worst?) was someone who came to the entrance, stopped, sat there for about 3 seconds and then went when there was a car coming in the roundabout and nearly caused a collision.
Roundabouts are unfair. They don't balance traffic loads symmetrically.
Here is what I have observed at one near my house: as you approach the yield line, you can't enter the circle if someone has just entered it on your left. So, if you have lots of cars approaching northbound, and lots of cars approaching westbound, the northbound cars will be on the left of the westbound ones, and will block their entry. You end up with a huge queue on the westbound lane.
This is exactly what happens every day at the evening rush hour (and of course the southbounders block the eastbounders in the morning).
A traffic light would be much better, because its red/green intervals can be tuned to observed traffic tendencies for the time of day.
There's two types of round-abouts: the Continental European kind and the UK/Australian kind. The UK/Australian kind are designed to keep traffic moving, so the angles are arranged to make entering similar to a merge. European ones are designed to slow traffic, so you enter at a right angle and have to turn hard to enter.
The UK/Australian kind kill cyclists[1]. I understand the European kind are safer, but I don't have personal experience with them (OTOH, I have been hit at a roundabout, and seen another 2 car/cyclist accidents).
Roundabouts don't kill cyclists, unobservant drivers kill cyclists. They kill cyclists on the straight and at intersections too. Don't blame the roundabout for it.
Roundabouts are great, dependent on traffic flow. If you have large amounts of traffic moving in one direction, it will prevent traffic flow from the direction that has to give way to it. In New Zealand, we use a lot of roundabouts, but often congestion easing requires replacing roundabouts with traffic lights to merge two incompatible streams of traffic.
I live in upstate NY, where the DOT is very passionate about installing roundabouts everywhere there is development, as they optimize use of undersized roads, especially in sprawly suburbs. (Search for "Malta, NY" on Google maps and check out the 6 consecutive roundabouts around the I-87 exit)
The problem is they are a cyclist/pedestrian death machine, and the bigger ones cause lots of small accidents. Looking out my office window, I've personally seem a strategically placed streetlight get plowed over about 8 times due to some of the engineering defects of this particular roundabout.
The roundabout in China pictured in the article included an elevated pedestrian walkway -- a feature nearly completely absent in US implementations.
The case of France is a quite simple. Governement wanted to lessen road related death, so they actually subventionned city and state to build roundabouts.
They are flourishing everywhere, but at this point there is not much need for it anymore. But they keep building them to keep their subventions, it redistribute money to local company (and also keep mayor in their place).
Sometimes you can drive 100Km without encoutering a single crossroad but hundred of useless roundabouts, it actually reduce speed on main road and provide little but no value to actual cross section.
Half* of the UK's roundabouts are in Skelmersdale, and they provide little function because there are so few cars on the road in the area. They probably increase emissions because you've got to drive that much further to get where you want (The largest of these roundabouts is half a mile in circumference) - and with nothing but grass, woodland and strange "art" sculptures in the middle, they're a huge waste of land.
I love roudabouts. I've seen the great use of them the very first time I've used them. I've always thought of traffic patterns as being the largest time suck of our modern lives. Two solutions to this. Install roundabouts or take over the stop light manufacturing and production in America with a startup. Sadly neither have happened due to the large need of capital to make either happen.
I hear the argument "Americans don't understand roundabouts, therefore we wont build any" quite often in these kinds of articles. If you survey people about something they've never comes across before, of course you're going to get negative results.
If Americans can drive and talk on their cell phones, they can handle a roundabout.
Obviously it will vary, but my experience in the suburbs of Minneapolis/St Paul (and driving in Europe and Australasia) has been the total opposite. Instead of stop sign hell every block causing gridlock during busy times traffic actually flows. "Minor car debris" likely comes from drivers who don't understand driving etiquette (use your bloody turn signal!) rather than road design.
[+] [-] tomohawk|10 years ago|reply
[+] [-] msandford|10 years ago|reply
So long as the traffic flow is at least the double-digits (mph or kph) roundabouts are just fine. Below that though, and there be dragons.
People tend not to jam up intersections with stop signs unless there's a bit of space for them on the other side of the intersection. Same for stoplights, although there are some cases where traffic backs up into the intersection though that generally has more to do with people who are moving (albeit slowly) and then everyone jams on the brakes all at once, stranding several in the intersection.
[+] [-] laurencerowe|10 years ago|reply
[+] [-] superuser2|10 years ago|reply
Drivers who are comfortable, having fun, and moving continuously are much more likely to speed and get in accidents than drivers who are annoyed and constantly vigilant for conditions changing second-to-second (like stop-and-go traffic).
[+] [-] saosebastiao|10 years ago|reply
It's not a problem when traffic is just congestion. It's hardly a common problem at all. But when it is a problem, such as is the case with a traffic accident that blocks multiple lanes of traffic, it causes full-stop gridlock to grow outward to the point of full paralysis.
The worst traffic jam I have ever been in was not in NYC, Boston, Seattle, or San Francisco, but rather in Idaho Falls, Idaho on a normally empty country road that was running parallel to the road where a drunk driver caused an accident that blocked the roadway. That single accident caused me and hundreds of other cars to sit in the same spot for almost 4 hours.
[+] [-] anon4|10 years ago|reply
[+] [-] ileitch|10 years ago|reply
[+] [-] mrb|10 years ago|reply
In both cases, traditional or roundabout, drivers are supposed to leave gaps in the traffic to at least let some cars through the intersection.
In both cases, if drivers don't follow that rule gridlock will ensue. In fact, 2-3 cars stuck in the middle of a traditional intersection is often all you need to completely block entry and exit traffic by preventing anyone from going straight or making left turns: https://en.wikipedia.org/wiki/Gridlock
[+] [-] timthorn|10 years ago|reply
[+] [-] Marazan|10 years ago|reply
[+] [-] seanalltogether|10 years ago|reply
Roundabouts aren't a replacement for stop signs, they are a replacement for stop lights.
[+] [-] knappe|10 years ago|reply
https://www.google.com/maps/@39.6439352,-106.3776606,248m/da... (2008 footage) https://www.google.com/maps/@39.6277372,-106.4200775,185m/da...
[+] [-] textingplan|10 years ago|reply
I once came upon it and found a full size four door sedan in the (raised) island in the middle with four befuddled teenagers standing around shaking their heads. They had plowed into the traffic circle straight ahead, jumped the raised embankment and landed right in the center island.
[+] [-] brc|10 years ago|reply
Late at night when there is no traffic it saves having to stop at all.
[+] [-] shawkinaw|10 years ago|reply
In Spain, basically everything is a roundabout, so much so that when the roads are big enough they have lights within the roundabout. That's way too much IMO.
[+] [-] enjo|10 years ago|reply
[+] [-] anotherevan|10 years ago|reply
My daughter recently got her learner license, and she has found roundabouts one of the trickier intersections to navigate. You have to read the traffic flow. This person about to enter on your right is going straight ahead, so will block you entering the roundabout[1], but they have to wait for that person coming the other way from you and going straight through, so you can slip in the gap that creates without cutting anyone else off. As with many things it is familiarity and practice that makes them work[2]. I think roundabouts work very well here for the most part, and my daughter is getting pretty good at reading the traffic. It’s not rocket science[3].
The science of roads and traffic I imagine is a surprisingly nuanced expertise involving a lot of physics and psychology. I find when I cross over the border to New South Wales I feel like a long-tailed cat in a room full of rocking chairs. I eventually figured out it was because the signage was a different distance before the intersection compared to my home state. Once I was aware I could adapt.
[1] We drive on the left side of the road because Australia is in the southern hemisphere.
[2] I bet the first traffic lights caused an uproar. “Why the hell should I stop just because there’s a red light?!”
[3] Oh wait, actually, it is rocket science.
[+] [-] grecy|10 years ago|reply
My parents just moved to Warrnambool from Mildura. One of their first comments was on the lack of roundabouts :)
[+] [-] dazc|10 years ago|reply
I encountered it once and don't ever intend to do so again.
[+] [-] grecy|10 years ago|reply
Upon moving to North America, it was shocking to encounter my first 4 way stop. To this day I still shake my head every time I encounter one. They are non-existent in Australia.
It's been amusing watching the resistance of North Americas to roundabouts, I think, because they are never taught how to use them. Sometimes I ask people the correct way to signal in a roundabout, and I swear I've never had two people in the same room agree.
The city of Calgary installed one, and it was taken out soon after because of a public outcry. In another city in North America I lived in, they put one in, and a lady promptly drove straight through it, crashing her car. She sued the city and one, because it wasn't fair to go and put in a roundabout like that.
[+] [-] slavik81|10 years ago|reply
[+] [-] davidw|10 years ago|reply
[+] [-] teilo|10 years ago|reply
The first problem is the people who don't know how to drive. I cannot count the number of times I have seen people stop in the middle of a roundabout to let cars in, or stop at the entrance and stare in confusion when there is absolutely nothing coming.
The second problems is inherent in the design. A line of traffic that is going straight can, effectively, prevent any cross traffic from entering the roundabout, due to the small radius of most US traffic circles. This is a trade-off, of course, and is still safer than traffic lights or a 4-way stop, and usually more efficient.
[+] [-] Zikes|10 years ago|reply
They think they're being polite, but they're forcing dozens of cars to wait for an additional cycle of the stoplight, whereas if they had just pulled through the light as normal then the waiting car would get a chance to merge as traffic either cleared or came to a stop again.
[+] [-] dwc|10 years ago|reply
I'm curious... where have you seen these troubles? Perhaps the small radius is the real issue?
[+] [-] brc|10 years ago|reply
The ignorance argument is difficult to agree with because every country has had to introduce them to an uneducated population at some point. You could have used the same argument against traffic lights.
[+] [-] jessaustin|10 years ago|reply
The point of roads is not to transport any particular traveler at the greatest possible speed, but rather to transport all of us in safe and convenient fashion.
[+] [-] monknomo|10 years ago|reply
I think the second problem is an acceptable tradeoff, but ymmv
[+] [-] aidenn0|10 years ago|reply
[+] [-] pmontra|10 years ago|reply
[+] [-] alejohausner|10 years ago|reply
Here is what I have observed at one near my house: as you approach the yield line, you can't enter the circle if someone has just entered it on your left. So, if you have lots of cars approaching northbound, and lots of cars approaching westbound, the northbound cars will be on the left of the westbound ones, and will block their entry. You end up with a huge queue on the westbound lane.
This is exactly what happens every day at the evening rush hour (and of course the southbounders block the eastbounders in the morning).
A traffic light would be much better, because its red/green intervals can be tuned to observed traffic tendencies for the time of day.
[+] [-] nl|10 years ago|reply
The UK/Australian kind kill cyclists[1]. I understand the European kind are safer, but I don't have personal experience with them (OTOH, I have been hit at a roundabout, and seen another 2 car/cyclist accidents).
[1] http://acrs.org.au/files/arsrpe/Cumming%20-%20High%20rate%20...
[2] http://search.informit.com.au/documentSummary;dn=38012654206...
[+] [-] empressplay|10 years ago|reply
[+] [-] EdwardDiego|10 years ago|reply
[+] [-] Spooky23|10 years ago|reply
The problem is they are a cyclist/pedestrian death machine, and the bigger ones cause lots of small accidents. Looking out my office window, I've personally seem a strategically placed streetlight get plowed over about 8 times due to some of the engineering defects of this particular roundabout.
The roundabout in China pictured in the article included an elevated pedestrian walkway -- a feature nearly completely absent in US implementations.
[+] [-] h1fra|10 years ago|reply
They are flourishing everywhere, but at this point there is not much need for it anymore. But they keep building them to keep their subventions, it redistribute money to local company (and also keep mayor in their place).
Sometimes you can drive 100Km without encoutering a single crossroad but hundred of useless roundabouts, it actually reduce speed on main road and provide little but no value to actual cross section.
[+] [-] sparkie|10 years ago|reply
*Approximation
[+] [-] JoeAltmaier|10 years ago|reply
[+] [-] dsfyu404ed|10 years ago|reply
>filling the center with landscaping that obstructs view
>putting them where a computer controlled light should be (small road meeting large road, stays green toward large road the vast majority of the time)
>put them where a flashing yellow/red should be (tiny road crossing main road
>putting roundabouts in areas that see a large volume of heavy trucks
Roundabouts don't work very well on roads with highly differing traffic volumes
[+] [-] spoiledtechie|10 years ago|reply
[+] [-] ileitch|10 years ago|reply
If Americans can drive and talk on their cell phones, they can handle a roundabout.
[+] [-] sandworm101|10 years ago|reply
[+] [-] jmount|10 years ago|reply
[+] [-] knz|10 years ago|reply
[+] [-] timthorn|10 years ago|reply
[+] [-] ourmandave|10 years ago|reply
https://www.youtube.com/watch?v=iAgX6qlJEMc