Hacking The Road: Roundabouts

If you are from the US, you might be surprised at how prevalent roundabouts are in most of the world. Outside of Carmel, Indiana which has 125 roundabouts, these are pretty unusual in the United States though have been gaining in popularity over the past decade. It turns out, that while a modern roundabout is safer and more efficient than other intersection types, roundabouts got a bad rap early on and so the typical US driver still has a lot of anxiety when approaching one.

Prior to 1966, traffic circles were a spotty thing. In some cases, they were just big circular junctions. In others, the right-of-way rules were difficult to figure out or there were traffic lights and stop signs that did not lead to a better or safer driving experience.

Enter Frank Blackmore. In the UK, he introduced the “Priority Rule” which — simply — mandates that traffic entering a circle must give way to traffic already in the circle. Blackmore worked out that this method increases traffic flow by 10%. Although this kind of roundabout became law in the UK in 1966, the US was slow to adopt, primarily due to negative public opinion. In 2016, there were about 4,800 modern roundabouts in the U.S while France and the UK have roughly 55,000 combined.

So what are the virtues of the modern rounabout, and where did it come from? Let’s take a look.

Modern Style

The modern roundabout has several features that were lacking on most older rotary traffic junctions. We already mentioned the priority rule. But a modern roundabout also requires cars to turn to enter the roundabout. This forces cars to slow and makes the intersection safer.

A roundabout is cheaper over the long run. There are no traffic signals to maintain and there is no power required. A single-lane roundabout can handle over 20,000 vehicles a day. The two-lane version can handle at least 40,000. Because there is less stopping and waiting, emissions are reduced, and the circles are more fuel-efficient, too.

Provably Safer For Cars, Less So for Cyclists

But the real pay off is in safety. Studies show that modern roundabouts are safer than other kinds of intersections for both drivers and pedestrians. A US study shows 39% fewer vehicle collisions, 76% fewer injuries and 90% fewer serious injuries and fatalities when an intersection changes into a modern roundabout. A New Zealand study did show, however, that bicycle/automobile accidents were higher at traffic circles.

It is a bit intimidating when you have a lot of streets feeding one circle. The Place Charles de Gaulle surrounding the Arc de Triomphe which has 12 roads feeding it. What really gets confusing is when you have multiple circles going different directions. The video below shows Swindon’s “magic roundabout” that has seven circles together!

Hack PR

You might consider this a civil engineering hack, but really we think the real interesting thing here is more social engineering. Just because you develop something better doesn’t mean people will flock to it. The US still won’t budge on using the metric system. The Dvorak keyboard remains an oddity (though it’s benefits may have been overhyped). People still write checks and use FAX machines. We still resist traffic circles.

Perhaps what Blackmore failed to consider is that in addition to tests showing the efficiency and safety of the roundabout, he should have also turned in a public relations campaign to convince people about the benefits. If you have the next great idea that will change everything, maybe you’ll take the Blackmore lesson to heart.

Usually, traffic circles don’t have lights, and we do like traffic lights. Especially the old fashioned kind.

108 thoughts on “Hacking The Road: Roundabouts

    1. A popular thing in my town of about 20,000 people is to pick a random intersection and slap a roundabout on it, offcentered in the direction that the city could get the cheapest land, so you end up with 3 streets right next to each other and the 4th on the opposite side. They also really like making them elongated for some reason.

      We have 6 or so and only two aren’t super messed up, it’s a great example of how not to do it.

    2. In France, if there are no roundabout signs then it is still a roundabout but the rules are different, traffic entering the roundabout has priority. Beware! The Charles de Gaulle roundabout (aka Etoile or Arc de Triomphe)is a case in point.

        1. The old rule in France was priority to entering traffic, that included traffic from a small side road having priority over traffic on a main road they are joining. Yeah, it sounds dangerous but people will learn to survive as best they can under any rules.
          Reforms were carried out a few years ago, a lot of white paint was put down, and most places changed but not all. There are towns that refused to change and the nicer ones put up warning signs on the principal roads into town. If you drive into a town and see a sign “Priorité à droite dans cette ville” slow down and keep your eyes peeled for vehicles driving straight out in front of you – most people don’t but they can.

      1. I have always assumed that the mini-roundabouts were there to establish right of way rather than an instruction to drive “round” the road markings.
        Never thought of them as counter-revolving city blocks though, so that’s given me a new mathematical model of the way they work. Excellent video, thank you.

      1. The Swindon Roundabout is pure evil. The six extra roundabouts are completely unnecessary. As an American, I was lucky to have been driving in the UK and Ireland for a couple of weeks when I came across it. Otherwise I would have been completely caught out.

    1. Yes I found out that left side driving is mostly ok when coming from right way (due to explicit priority mostly) but it’s totally un-natural to take roundabout this way.
      And lane switching in roundabout is quite different from france and uk: in france outer lane has always priority, in uk you must be on the external lane to quit the roundabout (and so you must exit when on the external lane).

      For bike single lane roundabout are ok, but a real killer on dual lane, especially if you cycle as mandated (outermost way), it’ s a recipe for being clipped.

      1. Scottish here (and commute past Edinburgh airport every day so the poster below is one of the lovely people I get annoyed at when they are in the wrong lane lol) .. I have noticed that in spain they *only* use the outside lane of a roundabout, even when taking the 3rd exit at a 4 exit roundabout. . takes some getting used too, as I always do it the “British” way.

    2. Applies the other way too. When living in mainland Europe I once flew to Scotland for a vacation. The moment I drove the rental car off the parking lot at Edinburgh airport I was faced with a cascade of roundabouts. Combined with the stick shift in the wrong hand and rear view mirrors on the wrong side my brain almost exploded.

      It’s amazing and scary how much of driving a car is subconscious.

      1. It’s comforting to know how much of it is subconscious – what would be the accident rates if you actually had to think about driving.

        One can go into road hypnosis and drive through a city without even knowing it happened. You react appropriately to pedestrians and traffic lights without paying any attention, automatically. This is actually the usual case, and whatever conscious attention you’re paying is mostly your self-narrating mind re-telling what’s happening. The unconscious mind is making all the choices and the conscious analytical mind has nothing to add to it, because there’s nothing that needs to be done differently, so it’s just pretending to be in charge.

  1. Americans can hardly comprehend simple road signage, so throwing a roundabout into someone’s life would just unleash mayhem. JK. Had a few of them back in Michigan, and people seemed to handle them alright. The real reason they’re rare is because we love sitting at traffic intersections, obviously. And besides, how else would we drag race from light to light?

    1. My only USA driving experience were 3 weeks in Las Vegas and I was actually quite impressed by native driving/reading skills. I’m used to simple signs + maybe an additional number that are processed automatically … and there I was reading “Absolutely no left u-turn for the next 2 miles” and completing the u-turn before my brain registered that was an actual road sign.
      And drag races were replaced by drifting, one has to break the rules somehow afterall.

    1. The problem with roundabouts is that they only really work correctly if the flow of traffic through them is approximately equal from all incoming roads. Otherwise, traffic already on the roundabout can prevent incoming traffic from entering; this is the reason for some authorities placing traffic lights on the roundabouts, allowing for a “fairer” flow. Generally they are only switched on at peak times, when queues build up.
      I know this because I live in Swindon, home of the Magic Roundabout pictured above. The Magic Roundabout actually works very well for it’s size, partly because a) people who know it know that there is more than one path to get where you’re heading, and b) people who don’t know it tend to drive very carefully through it. (Note that the Magic doesn’t need traffic lights, partly I think due to point “a)” above.)

    2. See MY later post! I am near the M2/A249 light-controlled roundabout in Kent (“They” are supposed to be building a fly-over – believe it when I see it!) but someone once ran into and completely demolished the traffic light control cabinet and whilst it was out of action, things were so much better, as inferred from YOUR post. When traffic gets back to “normal”, I shall be back down my short-cut rural route, as it’s purely the lights that cause all the horrendous backing-up at peak times. The “authorities” don’t seem to realise it!

  2. American drivers are too dumb to handle roundabouts and 9 out of 10 will stop whether there is a car approaching on not. They don’t even have sense enough to stay out of the left-most lane on the freeway (the “fast” lane) and you often find the slowest drivers blocking traffic there. Doh! And for some reason, if someone is stopped at the side of the road, 95% of drivers have to slow down to take a look, creating huge traffic backups.

    You may be thinking I’m wound a bit too tightly to be driving in the US, and you’re right.

    1. As an American I agree. The majority of people on the road shouldn’t have their license. Roundabouts might as well be useless because nobody knows what YIELD means and they just drive on through like the sign isn’t even there.

      1. South of Italy: I was sure I saw everything when some guy purpously went roundabout wrong way because it was shorter. But next day I saw a guy covering his eyes when joining the traffic to force me to give him priority.
        In some countries people stop in a middle of roundabout just to have a chat.
        Sure americans are dumb but they shouldn’t feel unique about that. Rest of the world is equally dumb just in a different way.

    2. U.S. drivers are not taught to merge from ramps to the expressway. Many seem to expect expressway traffic to yield to ramp traffic and play with cellphones while cutting across two or more lanes. Educators need to teach students to read the signs before reaching the circle and learn skills, such as tuning out all distractions when concentration is crucial.

  3. We have more then 70 rundabouts in the small city I live in, here they use them too often instead of building better roads.

    They built a new road to route the traffic around town for a better flow, and then proceedeed to make roundabouts in every intersection, instead of makeing on/offramps, so the traffic flow is really poor, especially in the 9 morhts of iceey roads, where all traffic around town needs to almost stop enery halfmile.

  4. All very nice, but my local UK council seems to have a habit of installing traffic lights on perfectly good, previously free-flowing roundabouts, which completely defeats the idea of a roundabout in the first place! To add insult to injury, quite often after some time has elapsed, they then announce plans to do something about the ever-growing congestion at one or more of the “improved” modified roundabouts – congestion that THEY caused in the first place with their crackpot, money-wasting schemes, which should be filed in the same category (marked “L” for “ludicrous) as so-called smart motorways with no emergency hard shoulder. The road planning folk certainly do work in mysterious ways.

      1. To paraphrase: on larger roundabouts the lanes are painted in a spiral, so you move outward as you continue driving round in your lane. All you need to do is pick the correct lane as you enter, and stick to it until you leave.

  5. >90% fewer serious injuries and fatalities when an intersection changes into a modern roundabout

    That’s simply because you can’t speed through a roundabout. That doesn’t mean people won’t try – that’s the remaining 10%.

    The only annoying bit about roundabouts is the fact that you can never get a green wave. Especially at night time with modern smart traffic lights, it’s common to be just able to drive long stretches of road without stopping. When every intersection is replaced with roundabouts, the whole thing becomes a slalom course that slows you down and forces you to brake and accelerate for no reason.

    “Serves you right, you selfish planet-destroying capitalist”, you might mutter righteously, until you remember that the ambulance service, the police and the fire department are slowed down as well, and large transports won’t fit through roundabouts so the goods have to be unloaded at distribution centers further away and brought in by multiple smaller trucks, so you burn more diesel to have food in the store.

    1. I don’t think I’ve ever hit a green wave. Have found plenty of roads with perverse timing that force you to speed if you don’t want to hit a dozen red lights in a row, though.

      > large transports won’t fit through roundabouts

      Only if they’re poorly designed. Tiny roundabouts are almost always bad, but then large trucks shouldn’t be on roads that would have a tiny roundabout on it. And there are roundabout designs that have a large plate around the centre that lets long vehicles like buses drive right over it while cars go around the outside.

      Can roundabouts be deployed badly? Very yes. Does that mean roundabouts are bad? Nope.

      1. We used to have these magnetic loops that detect cars entering the intersection, and if not they would just give green lights to anyone going down the main way. The lights would default to red, but when you approach the intersection it turns green. As a side effect, if you’re going over the speed limit, the light won’t turn green before you get a little too close for comfort and you have to start braking. Then just as you’re beginning to stop, it turns green.

        Large trucks used to go the same ways to have alternate routes into the city in times of congestion, but the local authorities deliberately put small roundabouts everywhere to stop them from getting through. They’re only just big enough for buses.

  6. “In 2016, there were about 4,800 modern roundabouts in the U.S while France and the UK have roughly 55,000 combined.”

    Got a source for that?

    55 thousand roundabouts is a lot.
    Sweden for an example has about 2.7 thousand roundabouts.

    France is a fairly large country and the UK builds a lot of roundabouts. (Though, Manchester and Glasgow are fairly devoid of them compared to many other cities of similar size oddly enough…) But I wouldn’t suspect that these two countries manages to have a combined 20 times more roundabouts in only twice the area compared to Sweden. (Though, the northern half of Sweden is a bit less dense when it comes to roundabouts, mainly due to a lower population density, so lets say 20 times more roundabouts in 4 times the area.)

    But still 55 thousand roundabouts sounds like someone hasn’t actually counted them and just thrown out a wild guess based on gut feeling or looking at an edge case and calling that the norm. (Like most sources on the internet, and why I settled down and started counting them manually…. Not to mention that not all “circular junctions” are roundabouts.)

    1. Sweden is 9 million, France and UK are 130-140 million people combined. Of course they have more roundabouts, because they have proportionally more cars and more roads. From that alone you’d expect 15 times more.

      1. Sweden currently has a population of 10.3 million.
        The UK has 67.8 million and France has 67 million, for a total of 134.7 million.

        Though, the UK is fun to count roundabouts in, since a lot of their circular roads doesn’t follow the more international definition of a roundabout. (Most countries considers a roundabout as a circular road where any traffic entering the road must give way to the traffic already in the roundabout. Ie, the circular road itself should never give way to oncoming traffic, nor be subject to traffic lights.)

        This means that a lot of “roundabouts” in the UK doesn’t even fall in line with how a roundabout is defined in a lot of other countries. (And we can’t really cherry pick definitions for each individual country when comparing them to each other. Since then one isn’t actually talking about the same thing. Ie, we should follow what most countries do agree on.)

        1. The vast vast majority of ‘roundabouts’ in the U.K. have priority to traffic on the roundabout. That’s what we call a roundabout in the U.K.
          The U.K. has loads of mini-roundabouts – At least in our area. They can easily be installed With a can of paint to alter the priorities at a junction. For better or worse. So the count is almost certainly correct.

      1. The vast majority of those country side roads have no roundabouts nor circular junctions.

        And most of the roads in the larger cities like Paris, follows a grid pattern, intersected by a few larger avenues, these avenues then do typically connect with each other in a handful of large roundabouts.

        There other cities do have a bunch of roundabouts, but nothing too impressive.

        Though, at the same time, I am not saying that Sweden has more roundabouts.
        Just that 55 thousand roundabouts for the UK + France is likely too high compared to what the actual number is.

        One can more reasonably expect them to have around 20-30 thousand roundabouts. (If it weren’t for some technicalities with the UK turning roundabouts into strange junctions…)

        1. Nearly every village has one. Not to say about small cities. They often put some kind of “decoration” in the middle, to deter drivers tempted to go straight, and force them to slow down.

          1. I have looked at hundreds of villages in both the UK and France.
            Exceptionally few has one.
            Most smaller cities has non, some have a handful of them, but most have non.

            Like some sources on the internet claims that France has half the world’s roundabouts. (BS I say.)
            Other sources claims that they have 60K+ roundabouts. (And some other sources state 30K.)
            While Spain apparently has 36000, the UK “has” 32000, and Italy has some 31000 of them somewhere…

            Where are all these roundabouts hiding? They sure aren’t on any maps I can find.

            For an example, I have counted some 2700 roundabouts in Sweden, and I literally can’t find any more. Yet, sources on the internet claims that Sweden has another 1100 of them. Where? I have systematically gone through every single town in the whole country, every road, every intersection.
            But apparently, there is 1100 more of them, likely in the 4th dimension.

            Though, some sources claim that Germany has 18K roundabouts, that seems like a somewhat logical figure for the size of the country, and given its population density. (but if you actually go and count them. Then no, there isn’t that many.)

            It feels like the whole thing with “The average person swallows 8 spiders in their sleep per year.”
            But with an added on, “and it increases by x every year”. (There is a good video on youtube called “the eight spiders” that goes to the bottom of that myth.)

  7. The new thing here are roundabouts but they are more diamond shaped than round. These work pretty well when you have a busy high speed road intersecting with a less used lower speed road. The more used road gets the long ends of the diamond and it is more of a swerve to continue on the road, the less used road has the more aggressive turn to enter the thing. I suspect that 4 way stops are safer than roundabouts but a lot less efficient. In the case of the diamond shaped ones, I am not sure they are much better than stop signs on the less used road, except for when the heavy use road does not have cars on it.

  8. That’s a pretty dumb take. You know what “give way” means, right? You don’t need to stop or even slow down at a roundabout with nobody in it. And surely you’re not going to try and tell me you’ve never been round a roundabout built for heavy vehicles? They’re just a little wider than usual, often with a section of the roundabout circle left traversable but marked for use by unwieldy vehicles only.

    I suppose I’m fortunate enough to live in a place where people actually get out of the way of emergency vehicles, I’ve heard that’s less common in places with fewer roundabouts :)

    1. Yes, roundabouts can be built to support larger vehicles. Though the slowing down part is generally recommended since more stuff can hide in one’s blind spot than one can imagine at times.

      Though, a well designed roundabout ensures that one doesn’t need to slow down much at all. And also get a sufficiently good view of any traffic in the roundabout to be able to safely stop. Though, there is also a lot of poorly designed roundabouts in the world…

      Then in some places in the world, tossing stones at emergency vehicles that arrives too late is a somewhat expected response. Not to mention blocking access for said vehicles, since clearly they shouldn’t get to pass… (Now, I wish I were ironic here….)

      1. When you put roundabouts in places where there used to be four way lights, what you usually don’t have is enough space to design it well, especially when you tend to get riders with the deal, like people demanding cycling lanes and walkways to be also built around the same intersection which make it even bigger. Especially in urban areas, the corner lots tend to be someone’s property and already built-in, and they won’t give it up cheaply.

    2. I’d like to see you take a typical roundabout at 40 mph, or faster for emergency vehicles.

      You can design a roundabout so that you don’t need to slow down, but it takes space and costs money so they tend to make them too small. There’s also the ideological pressure against cars in general, which means it’s an easy sell to pepper the place full of tight roundabouts in the name of “safety”.

      Most roundabouts around here, you have to almost stop to go around, and you can’t go half a mile before you hit the next one.They’ve filled downtown, the neighborhoods and their connecting roads with them – quite deliberately to inconvenience drivers – because they want to push the traffic onto the artery roads which are getting more and more congested by the day. Boon to the construction companies as well; they’re now building more lanes to deal with it.

      Translation: rich city hippies don’t want the poor working class people driving in and out of their city. They don’t own cars, so nobody should. If they could, they would ban cars entirely, but then you couldn’t get Uber…

      1. Most of the roundabouts I’m talking about are built exactly like this:

        https://image.shutterstock.com/image-photo/image-450w-356999459.jpg

        No sweeping curves – the road into the intersection connects radially without a separator, so you have to nearly stop to take the turn. These are peppered on every intersection where there used to be long stretches of road going through multiple neighborhoods, where you used to be able to drive straight through all green lights when there was less cross-traffic. Now if you want to go fast, it’s like Formula 1 at Monza.

  9. I used to live in Reading in the UK — pronounced ‘redding’ — and while it’s not the roundabout capital of the UK (that’s Basingstoke) it certainly tries hard.

    Roundabouts work really well, as they’re largely self-regulating, but have severe limitations. The first limitation is that the traffic must be equally balanced on all feeder roads, or you end up with starvation: imagine a three-road roundabout where most traffic travels A->B or B->A. Getting from C to A or B is very difficult because there’s always traffic coming on the roundabout and you never have right of way. You typically have to wait for someone to go A->C or B->C, which blocks the flow and gives you a gap to enter.

    The second limitation is that if you overfeed them they stall and block in all directions, leading to a very frustrating experience. The usual resolution is for the local council to put lights on them, which defeats the entire purpose of having a roundabout in the first place. You can sometimes help by putting bypass roads so that traffic which is leaving on the first exit doesn’t have to enter the roundabout at all, but usually at that point you need to give up and redesign the crossing. Of course, the councils hardly ever do and keep trying to patch around the problem, leading to this sort of thing: https://www.google.co.uk/maps/@51.4363465,-0.8979951,343m/data=!3m1!1e3 Yes, that’s a road straight across the middle of the roundabout. It’s all regulated by an incomprehensible set of lights.

    1. In a lot of countries, the definition of a roundabout is that it is a circular road where all incoming traffic must give way to the traffic already on the roundabout. This means that if a circular intersection is controlled by traffic lights, then it isn’t a roundabout by definition.

      Though, a lot of issues on roundabouts can be solved by offering a turn right lane. (or left for those driving on the left side of the road.)

      If one wants to build a road through a roundabout, then it is generally advised to elevate the roundabout, and dig a tunnel going under it for the straight connection. Or elevate the straight connection. (depending on what is more suitable for the area.)

      Putting up traffic lights for controlling a roundabout is a very poor solution, and should generally only be used in areas where control is of need. (For an example if one has a rail crossing, or heavy use of emergency vehicles like if the roundabout is next to a fire department.)

      Though, the worst type of roundabout is those that has a sloped access ramp, so that vehicles wanting to enter the roundabout not only have to judge the size of a gap, but also fight a literal uphill battle…. (A good roundabout should have a fairly flat access, at least for the last 5-10 meters.)

      1. >Though, the worst type of roundabout is those that has a sloped access ramp
        In the UK, motorway junctions are often designed so the roundabout for access roads is above the motorway, the idea is to help slow traffic down leaving the motorway.

    2. That roundabout is appalling. Can’t get round it without being stopped twice. The very similarly designed on on the A33/M4 junction works fine.
      It’s still a roundabout by UK definition even if it’s got lights. If/When the lights are off, the traffic on the roundabout has priority.

  10. Here in Arnhem, the Netherlands, the whole city ring is a roundabout. you can only drive counterclock wise. and because they synchronized all traffic lights of the ring, you seldom have to wait long.

  11. They sure take up much more land than a simple four/five way stop :) . And the center area can’t be used for anything useful. We got our first one west of town, getting off the interstate, into a round-a-bout. Works ok I guess. But then the old way worked fine too.

  12. A decade or so ago I gave up trying to explain to a couple of US friends how the Magic Roundabout worked and put together a short animation for them.
    They still thought it was nuts.
    So did I. On my first traverse I just followed the guy infront of me.
    But, it soon becomes just another junction, and at least no-one is moving very fast.

    https://youtu.be/kPANKRHL9HU

  13. Horrible.
    First they are too small so even if there is NO ONE even close you have to break, burning your breaks and will have to accelerate (I need to add the Rolling Coal option to my pickup). But any larger they woudn’t get property taxes.
    Second, you have to slow down because most idiots are incompetent to traverse them.
    Third, most streets have a priority difference. Instead of of an equally no power yield or stop sign for the lesser street, they do this more costly stupid thing.

    How many “roundabouts” shouldn’t just have a 2 way stop or yield?

  14. I’d be fine with the roundabouts in my town, but the traffic engineers in their infinite wisdom always put trees in the middle of them so you can’t see what’s coming around.

  15. Ok, This is where I need other people to weigh in on the proposed round-a-bout going in at the intersection where I reside.
    And yes, I am pretty much doxing myself, but I need others opinions. please go to google maps for an satellite view of the intersection.
    you can find some of the details on face book by searching “4th and obrien street round-a-bout”

    The reason I do not like this particular plan is, yes, while they do increase traffic throughput by 10%, the intersection directly south is going to remain (as far as I know) a 4 way stop. I am of the opinion that this increase of traffic will be restricted by the 3rd and obrien intersection, back up and clog the round-a-bout into a traffic jam.

    The obvious play would be to make 3rd and obrien a 2 way stop and allow traffic to flow easily, but having lived at this intersection for the past 18 years and witnessing how quickly people go between neighboring street, not having a stop sign there would be dangerous for pedestrians.

    I would also draw your attention to the size of the intersection, which is too small to put in a 2 lane version depicted here. I reside at the south west corner of the intersection and would loose a portion of my front yard.

    And the first person who says they should take my whole property can go to hell.

    I am not against round-a-bouts, I actually like them, they do make traffic flow easier. my reason for asking for more input is to see if others can see (or resolve for me) the potential problems I see with this particular one.

      1. Ok, I wasnt clear enough.
        We have a major factory (Cummins Engine Company) that when people leave work, they go through that intersection. I mean the only reason it MIGHT work is that while it’s unavailable for use while the circle is constructed, people might get trained to go the other way for a while and get out of the habit. But that’s only till the bypass construction gets started and they will HAVE to use the intersection. There is also the local Middle School that channels traffic through that specific intersection. From 3pm till about 4pm, that intersection is a nightmare.

          1. That makes sense in theory, but these are single lane both ways intersections. and the street is barely wide enough with parked cars. they would have to take some properties and make the whole street a no parking zone for that. This is a residential area, I don’t think that will be a good idea.

  16. The ban on engine braking (jake’s-brake) for big trucking makes a circle more of a overly complicated situation than need be. The real reason that the US don’t like them is we like being so productive behind the wheel with apps, texting and, handling things in the car whilst stopped waiting for the green. Getting by with just glancing at the screen propped up in the line of view (argh) and having to do some low speed Indy 500 outmaneuvers cuts into office and friends time. Oh! Suddenly driving a small agile car gets to be fun again. Our Purdue side has been getting a few circles and new areas have changed on both sides of town.

    Indianapolis has it, circles within both new and old. The crossroads of the capital break and encircle the Soldiers and Sailors monument encircled with classic early 20th century order, church, anchor department store, and Cinerama theater. Quite European! Then came the Interstate System and the big wheel, I-465 was drawn around the circle city. Carmel is best avoided, stay on I-465.

  17. The big thing here in Louisiana lately has been upgrading rural Interstate ramps with dual roundabouts, one on either side of the highway. They have made for a much smoother experience, even the one that serves three truck stops and so carries a lot of tractor-trailer traffic. It gives a lot of the benefits of a cloverleaf while using a lot less land.

    1. A lot of roads with on/off ramps here in the UK now have one large roundabout under or above the fast main road. It’s usually a good system except there’s often inconsistent lane use at the end of the ramp and on the roundabout. With regular use you get use to the foibles of each road layout, but on first visiting some of the more unusual ones it can be quite confusing.

  18. Here in arizona they seem badly implemented. There’s barely 2 lane and people hesitate getting on the roundbout and the flow is such that if you aren’t bold and jump-in, you can sit there behind a hesitant person for a long time. An example is the
    roundabout at the off-ramp of happy-Valley and I-17.

    1. what i hate about phoenix is grand avenue, (which for people who don’t know is a diagonal road in a grid city, which to make matters worse is parallel to the train tracks). of course a roundabout would interfere with grid traffic in this case and probably couldn’t be built without diverting the rails. we would often go out of our way to take indian school rd as that one had an overpass.

      granted i don’t live in phoenix anymore, last time i was there was 2009. big city living isn’t for me so i now reside in a small alaskan town on an island with less than 50 miles of roads on it. the traffic is still awful though which is weird because everything is in walking distance.

  19. its more a thing to do with american car culture. we want to go fast, we do not want to slow down every time we get to an intersection if we can avoid it.

    there’s also an urban planning aspect. there is really no reason to use roundabouts in grid cities (like phoenix), as most intersections are four way and you can synchronize the lights on busier roads such that cars following the speed limit can avoid stops. they do make sense in naturally formed cities where roads are in weird angles to each other and you have more than 4 roads at an intersection.

    we also have overpasses that look like a damn hot wheels set where you dont have to even slow down unless you want to switch roads, and even then you are not coming to a complete stop. these are usually part of the highway system, but are often used for in city traffic to save time.

  20. Here in the US they seem to be inconsistent. There is a brand-new one by my apartment (in a city with few or no others). It is elliptical. Why? It is one lane, except for a quarter of it, which is two lanes. What are the rules here? If you are in the circle and want to turn right in the 2-lane section, you MUST change lanes, but the people turning right in the outer lane believe they have right-of-way. Good luck figuring out the rules.

    A ski town nearby has several 2-lane circles. Nobody seems to know the rules. Markings on the road show which lanes you must be in for doing a half- or three-quarter-circle, but they are covered with snow throughout the season. There is no consistency, even from block to block.

  21. In the State of Idaho, USA, the capitol city of Boise doesn’t do its own road construction or maintenance. That’s all up to the Ada County Highway District. ACHD does pretty much whatever it damn well pleases with the roads, no matter what the Boise city government or the residents want, or don’t want.

    Roundabout right at the entrance to the VA hospital? Why sure! Don’t give a ^##^@ that the property owners at the intersection and a large number of residents and business in the area said they didn’t want it. They got it.

    ACHD has said they’ve plans for around 200 more of them in the coming years. https://boisedev.com/news/2019/08/22/what-comes-around-long-range-plan-could-add-nearly-200-roundabouts-to-ada-county/

    One of the first out here was in Canyon County, in the middle of nowhere. Note it was designed by a numbskull who figured that lumping it up and putting big plants in the middle to block vision across the intersection was the greatest idea ever. https://www.google.com/maps/search/Happy+Valley+Rd.+Idaho/@43.5611481,-116.5140773,399m/data=!3m1!1e3

    Then there’s this dogbone roundabout monstrosity. https://www.youtube.com/watch?v=fEJf6rh_h8s

      1. I suspect that’s intended to be for the benefit of large vehicles (eg lorries/trucks) so that they can encroach on the roundabout without worrying about bashing a crash barrier.
        This video does remind me of something that happened near me some years ago: like in this video a car didn’t slow down for a roundabout, but they weren’t going as fast so instead of launching the nose of the car grounded and the back lifted right up to the sky. It didn’t tip over though, it just stayed upright like the monolith from 2001.

  22. Starvation! Utah seems to be in love with these demons, and on a road, say with a strong north/south flow, the north south entrances will be full, causing tremendous wait times for those entering from the east/west entrances. Which of course, causes people to go find routes without the demons to get to the north/south entrance, compounding the problem.

    Also, horrible drivers think you have to go 5 MPH around them. Couldn’t possibly register even 0.1g of acceleration in an direction! That’s getting more typical, especially as insurance companies add spy devices to their policies which ding you for “high” accelerations, as those are clearly signs of a terrible driver! So instead, we must all be timid. Sadly, more and more people are signing up for spy devices. They’re pretty easy to spot on the road. Combine them with circles, and its a recipe for traffic jams. Even without the spy devices, I think American’s, as a whole, are becoming the most timid drivers in the world. Seen way too many cases of stopping in acceleration lanes for the highway, preemptive braking for the traffic light that may turn red 1/2 a mile away, and the slowest turning one could possibly imagine. No skill at all. Circles just compound all the problems. Don’t worry Europe, if the policies that have driven this lack of driver skill haven’t reached you yet, they likely will at some point.

    I do love getting to the circle with traffic near enough to see, but far enough to let me through. Then I show the imbecile driving a Porsche at 5 MPH through the circle that a pickup truck can manage the same feat at 25 MPH. I could probably do 35+ with that Porshe!

  23. My wife and I were eased into the RHD+roundabout learning curve by starting in a regional town in Oz. Having cracked the code, we opted for the advanced course in the UK, and graduated by taking our RHD vehicle across the continent on road trips. Avoided the Place Charles de Gaulle, but didn’t have a problem otherwise. Treating the roundabouts as California road rule yield on right (UK: left) turns has seemed simple enough.

  24. “modern roundabout is safer and more efficient than other intersection types” LOL!!! You must not live near all the completely retarded drivers I have to deal with every day. Most people in USA come up to a roundabout and A: slam on their brakes for no reason, or B: accelerate through it without yielding to traffic… …at least with a Red light camera, you have evidence they were the cause of the crash… with a roundabout, good luck!!! I despise roundabouts simply because our fellow Americans are 99% bad drivers at heart.

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