
The Case for More Traffic Roundabouts - Oletros
http://priceonomics.com/the-case-for-more-traffic-roundabouts/
======
tomohawk
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.

~~~
msandford
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.

~~~
toxik
In Sweden we have a lot of roundabouts (and we also love to brag about having
the world's lowest road fatality rate) -- what I see a lot for big roundabouts
is traffic lights before entry. Best of both worlds.

~~~
tomohawk
With the lights on the roundabout entry points, it flows better than a regular
signaled intersection, as left turns are no longer an issue.

------
saosebastiao
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.

~~~
anon4
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.

~~~
mrb
_" your path is constantly crossed by drivers going straight through, doing a
right turn"_

It's only crossed by the same amount of drivers than a regular intersection:
those going on the same street as you.

 _" They are all driving at full speed"_

Actually no, the curve of the roundabout (for properly designed roundabouts)
slows them down. In fact a traditional intersection causes them to drive even
faster since many drivers go in a straight line.

 _" It is a delicate game"_

The nice thing about roundabouts is that you only have to check for cars
coming from ONE direction, as opposed to a traditional intersection where cars
can come from behind you, from your side, or from in front of you. So crossing
a roundabout requires less cognitive bandwidth.

~~~
_delirium
At busier intersections I find traffic signals much nicer as a pedestrian,
because while the same number of cars do cross your path, they don't cross
your path _when you have the walk signal_ , which is when you'd actually be
crossing the intersection. It gives you a nice break in traffic rather than
having to push your way out and hope traffic stops for you. This is assuming
no right turns on red (as in most of Europe), and left turns only on left-turn
signal (typical in cities, at least on major roads). In those cases, there is
no traffic at all allowed to enter the crosswalk when you have the walk
signal, so you have an exclusive protected crossing.

At lower-traffic intersections the difference is less pronounced, partly
because it's easier to force your way across even without a signal, and partly
because the signals at less busy intersections may not give pedestrians an
exclusive period in the cycle anyway (e.g. by allowing left turns on a regular
green).

This might be Copenhagen-specific, but in Copenhagen I also find roundabouts
make the pedestrian/bicyclist interaction less clear. At regular
intersections, bicyclists can't cross your path when you have a walk signal,
but at roundabouts they seem to just go through and are less likely than cars
to stop preemptively when they see a pedestrian wanting to cross. Roundabouts
aren't very common though, so maybe this would be worked out if there were
more of them.

~~~
mrb
_" I find traffic signals much nicer as a pedestrian"_

You may find them nicer, but they are not safer. The data already shows
roundabouts are safer. As the article reports: _" researchers have found that
roundabouts reduce [...] pedestrian/cyclist incidents by 40%"_

~~~
_delirium
That study was specifically in the USA, whose signalized intersections are not
really pedestrian-friendly to begin with. For example right-on-red is
permitted almost everywhere (except NYC). In that context, I could believe
that roundabouts are less bad. I would be interested to see how the comparison
generalizes, for example a study of roundabout vs. signalized intersections in
Denmark or Germany. It's still of course possible my feeling of more safety at
signalized intersections in Denmark is wrong.

Sweden takes an interesting approach in combining both. There are a lot of
roundabouts, but most of them _also_ have a signal at the entrance. This makes
it easy to cross as a pedestrian, because your crosswalk at the roundabout
entrance is protected with an exclusive signal cycle. That forces a gap in
traffic instead of you having to force the gap by trying to step out. Possibly
even safer than either option alone?

~~~
Tomte
I don't have a study at hand, but in Germany, too, it is generally accepted
that roundabouts are safer.

------
seanalltogether
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.

~~~
knappe
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.

[https://www.google.com/maps/@39.6439352,-106.3776606,248m/da...](https://www.google.com/maps/@39.6439352,-106.3776606,248m/data=!3m1!1e3)
(2008 footage)
[https://www.google.com/maps/@39.6277372,-106.4200775,185m/da...](https://www.google.com/maps/@39.6277372,-106.4200775,185m/data=!3m1!1e3)

~~~
lisper
That's actually Vail, not Aspen.

~~~
knappe
Yeah, you're right. I had the maps right, but name wrong.

------
anotherevan
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?!”

[3] Oh wait, actually, it _is_ rocket science.

~~~
grecy
> _Having too many of them instead of give-way signs drive you a little batty
> (I’m looking at you, Warrnambool)_

My parents just moved to Warrnambool from Mildura. One of their first comments
was on the lack of roundabouts :)

------
dazc
You can't discuss roundabouts without a mention of the magic roundabout in
Swindon, UK. A big roundabout made up of 5 small roundabouts.
[https://en.wikipedia.org/wiki/Magic_Roundabout_(Swindon)](https://en.wikipedia.org/wiki/Magic_Roundabout_\(Swindon\))

I encountered it once and don't ever intend to do so again.

------
grecy
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.

~~~
slavik81
There's a bunch of roundabouts in Calgary, though admittedly they're not
common.

------
davidw
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.

------
teilo
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.

~~~
Zikes
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.

~~~
shkkmo
"dozens" is quite a bit of hyperbole. I generally only see behavior like this
when traffic is dense and the speed of traffic is limited. In those cases,
letting someone in doesn't decrease the number of cars that make it through
the light. Additionally in those cases, it's quite possible that if nobody
lets in the the car trying to merge, they will never be able to merge.

Obviously, optimal behavior is dependent of the traffic conditions.

~~~
Zikes
"Dozens" is not hyperbole at all, my account is an accurate and truthful
statement of the traffic conditions in my area and the consequences of those
bad actors.

Cars looking to merge should do so as the traffic comes to a stop. A car
already on the highway they are looking to merge onto need only stop sooner
than they otherwise would, allowing them to pull out into traffic that is
already at a standstill.

~~~
shkkmo
I'm not sure I understand the traffic conditions you are describing.

Lets take "dozens" to mean "atleast 18" (a dozen and a half). The average car
is 15ft so this means to fit the 18 cars bumper to bumper there will need to
be at least 270ft between the car you let in and the car in front of it when
it passes out of the intersection.

If you leave half a car length between cars and allow the full 2 dozen this
number quickly becomes 528ft.

If people are really this slow in pulling out, I feel your pain. However it is
these numbers that caused me to judge your anecdote as hyperbole

Additionally, you suggested blanket solution sounds more dangerous as well as
completely unworkable in bumper to bumper trafic: "Cars looking to merge
should do so as the traffic comes to a stop."

It's far more dangerous to pull out in-front of a moving and already braking
car that may or may not see you then to pull out in-front of a stopped car
that has indicated that it does.

------
pmontra
The most straightforward designs of roundabouts don't have a good safety
record for cyclists. This post gives some hints based on the Dutch experience
[http://www.aviewfromthecyclepath.com/2014/05/the-best-
rounda...](http://www.aviewfromthecyclepath.com/2014/05/the-best-roundabout-
design-for-cyclists.html)

------
alejohausner
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.

------
nl
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).

[1]
[http://acrs.org.au/files/arsrpe/Cumming%20-%20High%20rate%20...](http://acrs.org.au/files/arsrpe/Cumming%20-%20High%20rate%20of%20crashes%20at%20roundabouts%20involving%20cyclists%20can%20be%20reduced.pdf)

[2]
[http://search.informit.com.au/documentSummary;dn=38012654206...](http://search.informit.com.au/documentSummary;dn=380126542062424;res=IELENG)

~~~
empressplay
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.

~~~
nl
That's correct of course. However, roundabouts increase the risk enormously. I
assume you read the stats in my links?

 _49% of crashes at roundabouts involved cyclists_

It specifically addresses the "look but didn't see" problem, and how the
Australian design makes that worse: _Herslund & Jørgensen videoed cars and
cyclists at roundabouts and noted that bicycles are often located in drivers’
peripheral vision. They suggest that experienced drivers use fast search
strategies such as concentrating on where cars usually are, so may be more
prone to LBFTS collisions than less experienced drivers._

------
EdwardDiego
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.

------
Spooky23
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.

------
h1fra
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.

~~~
sparkie
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.

*Approximation

~~~
JoeAltmaier
The most curious definition of 'waste of land' I've encountered in a while.
Are national parks also a waste? How about wildlife refuges? Oh! Scotland!
That may also qualify.

~~~
sparkie
National parks are places of outstanding beauty. I can assure you Skelmersdale
is not.

By waste of land, I mean the place was built using several times more land
than was needed for the relatively low population, but some clever fool with
government money decide they'd build a bunch of small ghettos separated by
large roundabouts.

~~~
JoeAltmaier
Sounds miserable. I was imagining a bucolic wonderland of natural beauty, with
birds nesting and ancient oaks over shady glens.

My local town is in the process of sticking 'roundabouts' everywhere. Mayor
visited someplace and liked them; he's pushing them on us now. Sometimes its
just a dumb island in the middle of an intersection; you have to crank around
it at microscopic speed which benefits no one.

The worst one has two lanes halfway around; one lane the rest of the way. From
the south you can take the right lane and exit north without turning (much).
But nobody understands the point; everybody stops and creeps around. So they
put up a map(!) so you can figure it out. And 13 arrows and warning signs. All
in the interest of 'efficiency'

------
dsfyu404ed
A large problem with roundabouts is that municipalities tend to build them as
poorly or put them places where a light should be.

>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
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.

------
ileitch
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.

~~~
hessenwolf
Somebody gave me the argument in NASA that the US didn't switch metric because
the cost would be too high because they are so big. Ireland and UK have gone
metric in our lifetimes.

I mean, there are lazy people throwing out platitudes to justify doing nothing
wherever you go.

------
sandworm101
More, but only those little ones where the island is smaller than the road so
that motorcycles can fly strait through.

------
jmount
Small roundabouts do not work. Here in San Francisco the small ones (out in
the burbs) jam up with few cars and are littered with minor car debris.

~~~
knz
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.

------
ourmandave
The Case Against Traffic Roundabouts.

[https://www.youtube.com/watch?v=iAgX6qlJEMc](https://www.youtube.com/watch?v=iAgX6qlJEMc)

