Safety benefits of roundabouts

Simple roundabouts are definitely good but in UK I have found spiral roundabouts error prone if you have not driven on it before Example: [1]<p>When visiting for the first time on a specific spiral roundabout:<p>1. Lane markings are faded<p>2. You do not know the specific lane unless you come very close to it and have to make a quick decision<p>3. Often due to queued traffic you cannot even see the lane marking until its too late.<p>Because of this I have seen people change lanes on a roundabout because they made a mistake and its dangerous.<p>[1] <a href="https:&#x2F;&#x2F;www.google.com&#x2F;maps&#x2F;place&#x2F;Sainsbury&#x27;s&#x2F;@51.5080462,-0.5816409,173m&#x2F;data=!3m2!1e3!5s0x48767ab1f69dfbc7:0x480bc3e7f0621fd4!4m6!3m5!1s0x487664d7ccdb3e33:0xdc0fd0ed013eb0d1!8m2!3d51.5080945!4d-0.579077!16s%2Fg%2F1ptvv67nn?entry=ttu" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.google.com&#x2F;maps&#x2F;place&#x2F;Sainsbury&#x27;s&#x2F;@51.5080462,-0...</a>

Two lane roundabouts are pretty good. More than two lanes are very questionable. And roundabouts which include... stoplights!?!? are just stupid.<p>I live in the Netherlands, where roundabouts are very common. In many cases, they are an improvement.<p>But NL is also a huge bike country. And at most roundabouts, bikes have right of way. So as a car driver, you have to worry about other cars as well as bikes which may turn (go away from the roundabout) or continue (cross the adjacent road circularly around the roundabout.<p>In good visibility conditions, it&#x27;s ok. And by OK, I mean it can still really f* up car traffic, especially when it is a high traffic area not far from a school. In lower vis conditions, and&#x2F;or when electric higher speed bikes are concerned, it becomes a whole new kind of danger.<p>I would argue that the benefits of roundabouts diminish or fully disappear when the number of lanes exceeds 2, or when traffic lights are added to roundabouts, or (and!) especially when bike paths intersect with and circulate around the roundabouts.

If you like roundabouts, try a roundabout of roundabouts: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Magic_Roundabout_(Hemel_Hempstead)" rel="nofollow noreferrer">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Magic_Roundabout_(Hemel_Hempst...</a><p>This is near where I live and it is indeed safe, mainly because everyone drives incredibly slowly and cautiously since the experience is scary as hell.

Ctrl+f &quot;pedestrian&quot;<p>Only one result and it&#x27;s not even about roundabouts.<p>This is how American traffic engineering is done.

Swindon, UK would like to remind the World that recursive roundabouts are a thing too.<p><a href="https:&#x2F;&#x2F;i.imgur.com&#x2F;4pMhdMl.gif" rel="nofollow noreferrer">https:&#x2F;&#x2F;i.imgur.com&#x2F;4pMhdMl.gif</a>

Here&#x27;s an explainer on &quot;conflict points&quot; [1] which seems central to the argument. Most folks intuitions are correct that roundabouts eliminate cross-traffic (major conflicts), but they also reduce merge, diverge and weave conflicts (minor).<p>[1] <a href="https:&#x2F;&#x2F;www.apsed.in&#x2F;post&#x2F;conflict-points-at-intersection" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.apsed.in&#x2F;post&#x2F;conflict-points-at-intersection</a>

I like roundabouts but American drivers on average have no idea what to do with them, not even from a common sense perspective. To be fair, American drivers are vanishingly able to handle four way intersection, but I digress.<p>There are two roundabouts near me. The same two problems are rampant.<p>1. Failure to yield and yoloing into the circle at or nearly at full speed. One of the circles has a full stop sign, where some drivers seem to think that just because they stopped they are entitled to go next and the traffic already in the circle should and will stop to let them go, like a four way. The other doesn’t have stop sign, and I think people take the lack of one to mean they don’t have to yield or in any way pay attention because, hey, no stop sign. Admittedly, part of this is due to shitty design of the circles themselves.<p>2. Cars in the circle suddenly exiting without signaling, often veering across the outer lane of traffic. Part of this is driver’s education issue (I don’t think they taught us about roundabouts when I got my license several decades ago), part is the fact that in general people are allergic to signaling and have no awareness of other vehicles around them, as we have the same problem on highways.<p>Perhaps this is more of an awkward transitional period for their use in the States, but honestly I think the bigger problem is we on average have very poor roadmanship and inconsistent road design.

In the Netherlands we had a huge phase of replacing regular crossings with roundabouts, which I consider to be an improvement. Now, however this is followed by a re-engineering phase of many of these roundabouts. The 2-lane ones, where a driver needs to pre-select whether they want to go a quarter round (turn right in Netherlands) or select for straight-ahead and 3 quarters round. The lanes on these roundabouts are separated by a rather high ridge to avoid drivers changing their mind and change lanes. This probably done for safety, except that they feel more unsafe now, by introducing &quot;choice stress&quot; upon entry of the roundabout, especially if the road directions aren&#x27;t very clear. To me it feels like over-engineering.

I’m from rural Ireland, and I always remember my first roundabout - I used go driving with my dad when learning, and as the weeks progressed I’d get closer and closer to Killarney which was the nearest town. Coming from our side the first thing you meet is a roundabout with 3 exits, one bringing you out the roads that bypass the town, one to the town centre, and one to a housing estate off the roundabout. As I joined the roundabout I met a woman driving against me on the roundabout taking a shortcut to her exit of the housing estate - frightened the shit outta 16 year old me, my dad was spooked too. I managed to make room enough for her to pass - she was oblivious. My dad actually knew her, lived there all her life, she must have driven that road 1000 times - how often was she taking that shortcut

I grew up in a town in Australia nicknamed &quot;The City of Roundabouts&quot;. Essentially all intersections in the entire town are roundabouts, including two lane ones, etc. It&#x27;s quite common to drive the entire length of town (~20 blocks) in reasonably heavy traffic without ever stopping. On a good day you do it in 2nd gear, the whole way. At night you can do it in 3rd gear, because it&#x27;s exceptionally easy to see headlights of any car you need to yield to.<p>Four way stops do not exist (I&#x27;ve never seen one in all of Australia), and they are still the strangest concept for me living in Canada. They feel like a colossal waste of time and energy, and vastly worse than roundabouts.

The greatest thing about roundabouts is that they protect against the idiot that goes through an intersection at full speed. He does that either because he is passed out behind the wheel or because he did not notice a stop sign and thought he had the right of way, or maybe because he just does not care.<p>Well with a roundabout if you just go straight ahead you hit the center circle. Good roundabouts always have a slight hill and some kind of barrier (a tree or some kind of statue) in the center so that the guy that just goes straight through will hit something in the center and wont come out the other side and will thus be less likely to kill an innocent person.<p>Single lane roundabouts are usually a good idea if the cost justifies it. Double and more lane roundabouts probably should be avoided in the US; they include rather obscure rules as to which lane you are allowed to drive in at any moment and americans do not like to learn new rules.

Inexplicably, the ones in the Bay Area are often installed with stop signs, which makes the point of a roundabout rather mysterious.

In Spain we use roundabouts heavily.<p>They&#x27;re perfect for crossings with low to middle traffic. No useless waiting time, good visiblity and no need for traffic lights.<p>For heavy traffic, though, they&#x27;re useless as the car flow of one entry&#x2F;exit can take over the roundabout and block all other entries.<p>Also, it seems hard to understand for many drivers that regulations regarding changing lanes don&#x27;t change in a roundabout. So more than 3 lanes are not advisable in my opinion.

Roundabouts for high traffic areas are good. The problem is when they are overused in low traffic areas where they create obstacles to efficient continuous motion, increase pollution, and waste time.<p>PS: One place that doesn&#x27;t do proper traffic design (or architecture): Texas. They insist on placing massive concrete dividers everywhere and have camouflaged by wear obstacles in the middle of paths that are injurious to bicyclists. It&#x27;s nothing like the Netherlands where there aren&#x27;t many random, dangerous surprises.

Personally, I&#x27;m fine with the simple single-lane roundabouts. They&#x27;re convenient for U-turns, for example.<p>For anything above that where I have to cross lanes to get to the center circle and then cross lanes again to get back out and exit, I&#x27;d rather just have a conventional traffic light-controlled intersection. (I try to minimize lane changes when I drive.)

Portland, Oregon has a roundabout with four stop signs and I&#x27;ve been mad about it for thirty years. Why?!

Here in France they have both types of roundabouts, yield-to-left-on-entry and yield-to-right. They are well signaled, so there is no confusion. The latter type is less common and seems to be mostly in less-busy areas. I&#x27;m not sure why they still use them though. Is it because you have better visibility to the right, since you&#x27;re already in the intersection? It&#x27;s an interesting design choice.

Safety aside, roundabouts lower traffic significantly by never forcing cars to stop. Congestion increases as cars need to stop because of the inevitable latency propagating along the tails, and having more than one traditional intersections along the way can only make things even worse, so any solution to prevent cars from slowing down to a stop would mitigate those effects.

Amazing to see a &quot;What is a roundabout?&quot; article living in UK. The way they are put in over here you get the idea traffic engineers not only love them, they are in love with them. I largely detest them, if I&#x27;m very honest. They can be done really well, but most aren&#x27;t.

Interesting that there are no listed downsides. I saw a more balanced article a while back and recall that it listed cost (especially of the additional real estate, since roundabouts are larger) as being one downside. And in built-up cities, it&#x27;s basically impossible to convert traditional intersections to roundabouts, because there&#x27;s simply no room.<p>It is nice to not have to pay for replacement signals, or have to deal with power outages that kill the signals though.

What confuses me on roundabouts is the intended speed. Some are very tight and requires slowing down to 15mph and others can handle faster speeds. Rarely is the intended speed marked.<p>A new roundabout in Brevard, NC has a very tight turning radius. There is a sign warning drivers in the outer lane to watch out for tractor trailers who will have to take both lanes to navigate the circle.

When my wife and I moved to Bend, Oregon from Italy, I was really shocked to see how much the city had embraced roundabouts. I hadn&#x27;t expected to see any in the US, let alone more than 20 of them throughout the city.<p>Not quite sure what the exact history was, but they realized a few years back that they cost less and work pretty well.

I grew up in a touristy part of New Jersey near the beach and roundabouts were interesting. In the off season they were a fine and normal part of driving that the local population were generally used to. Occasionally you’d have a new driver or out of town person that would be confused but that was somewhat rare.<p>Then the summer months would come and the circles would be a nightmare, filled with dipshits from the surrounding states that had no idea of how they worked despite the fact that the majority of them were single lane! You would really dread the double lane ones though as they would be filled with people who would have no idea how to proceed. You would often see people go around several times before they’d finally exit when there was a lull in traffic

Roundabouts work well in my country, mostly, even the three lane ones. However a few weeks ago my wife encountered someone who obviously had a moral objection to the &quot;round&quot; in roundabout and drove in the straight line across three lanes of the traffic to the exit.

I&#x27;m not a traffic engineer, but I think roundabouts take more space than an equivalent signal or stop sign intersection. The article says that many places are starting to default to roundabouts, but many intersections are likely going to be difficult to upgrade.

I love roundabouts. Driving in the UK is a revelation. You just sort of keep going and driving is a bit more fun. The drivers are also better than in the USA. Which is why I think there’s often resistance here.<p>Every time a roundabout is proposed near me there’s a vocal group of opposers. I just don’t really get it since in many cases a roundabout is preferred to an intersection in my opinion. But one comment I read summarizes it I guess:<p>“Drivers here are just too dumb for a roundabout. We can trust them to think.”<p>And I guess I sort of agreed. Driving in America is weird because so many people do things like passing on the right, not using turn signals, and driving the wrong speed in whatever lane they’re in causing chaos.

Allow me to explain why at least one of them is so annoying. The roundabout is atop a hill; there is little visibility of what traffic is approaching from other directions because the hill is steep. Motorists don&#x27;t bother signaling how far around they will go. I, riding a bicycle on a sidewalk, wish to go straight across the road. However I can&#x27;t always see that someone is entering the circle. And even if I do see someone is entering, I don&#x27;t know when they will exit. Compare this to an ordinary stop-signed intersection, where it is clear when vehicles are not turning and I can directly cross.

Long time Carmel, IN resident here, AMA. Yes, almost every intersection has a roundabout for a population around 100k. Yes, they are efficient. Yes, it’s a pain using them when people who don’t know how to use them, use them.

Big fan of roundabouts - generally they keep the traffic flowing much better than lights and work well for cars.<p>However if I&#x27;m on a bicycle, or I&#x27;m a pedestrian trying to cross the road near them, they can be more dangerous.<p>There is a special kind of roundabout that is designed to tackle this issue - the so called dutch roundabout ( at least in the UK :-) ) however it does require drivers to know how it works - so there is always a chicken and egg problem as you introduce them.

Roundabouts also don’t work so well in our ever more narcissistic society due to:<p>- lack of indicating of taking an exit which which impedes the flow of traffic of the vehicles who thought they had to stop to give way<p>- blocking entrance to the roundabout when someone’s exit has traffic<p>- in heavy traffic, aggressively maintaining the normal give way rules instead of doing 1 for 1 for a fairer movement of vehicles<p>Not that I’m arguing &#x2F;for&#x2F; 4 way stops. I just think roundabouts work pretty well when you abide by the rules and apply some courtesy and respect.

Couple of things that go wrong with roundabouts:<p>2 lane roundabouts where the inner lane needs to give priority to then outer lane. The Netherlands does it a lot better with lanes that &#x27;tear off&#x27;, and you migrate naturally to the outside line.<p>Roundabouts on roads with lots of North&#x2F;South traffic can cause people who come from East&#x2F;West to have to wait forever as they can&#x27;t just jump on the roundabout. As long as traffic is coming and can enter the roundabout they don&#x27;t have to allow anybody else on it.

One thing I love about roundabouts is the efficiency of the algorithm, compared to the classic semaphore-controlled crossroads.<p>Since the inbound cars are required to yield to cars that are already inside the roundabout, the cars inside the roundabout are always guaranteed to exit the roundabout in a reasonable amount of time (assuming the exit lanes are not blocked), which means that there will always be new empty spaces for inbound cars to enter in an opportunistic way.<p>It feels kinda like Ethernet for traffic.

Hey kids. Big Ben. Parliament.<p><a href="https:&#x2F;&#x2F;youtu.be&#x2F;iAgX6qlJEMc?feature=shared" rel="nofollow noreferrer">https:&#x2F;&#x2F;youtu.be&#x2F;iAgX6qlJEMc?feature=shared</a>

The just-released Cities: Skylines 2 video game also features roundabouts! They&#x27;re a huge part of the transportation networks now: <a href="https:&#x2F;&#x2F;www.pcgamesn.com&#x2F;cities-skylines-2&#x2F;roundabouts" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.pcgamesn.com&#x2F;cities-skylines-2&#x2F;roundabouts</a><p>Mini Motorways also had them from the get-go, and they&#x27;re much more robust than simple 3&#x2F;4&#x2F;5&#x2F;6-way intersections.

My experience is that roundabouts help but don&#x27;t solve. E.g. if there is a complete traffic jam, you may actually increase the risk of collision due to negotiations about right of way happening every time a car can move forward.<p>Some cities in Europe have so many roundabouts, and two or three lane roundabouts with complex exit decisions you need to make on a split second - it&#x27;s actually very confusing to navigate.

Roundabouts are SHIT - especially so when they eventually acquire traffic lights - leading up to them, and finally actually on them...<p>In the UK its priority to the right, meaning if there&#x27;s something coming around the roundabout, you must&#x2F;should wait... Which only works of there is a gap in the flow of traffic big enough for you to jump into...<p>Don&#x27;t worry USA, you&#x27;ll soon regret your decision to introduce roundabouts.<p>Stick with your sensible &quot;right on red&quot; logic, and your sweeping circular on&#x2F;off ramps (yeah, you and Canada have plenty of space to do those) - they are genius for maintaining traffic flow (not so convinced about the traffic lights leading onto the freeway though at rush hour times!)<p>If you fancy a giggle of what mayhem roundabouts can cause, try searching for &quot;spaghetti junction&quot; near Birmingham England, or &quot;the magic roundabout&quot; of Swindon England fame - they are priceless!<p>Enjoy! ;-)

I could see how these have benefits in some cases. There are also drawbacks… the uncertainty of who is yielding (except maybe by AI). What about snow and ice? If you do some searching there are plenty of reasons why you might not want roundabouts.

Half the videos on Dash Cam Australia are roundabout accidents.

Learning to handle a 3-lane wide roundabout outside Inverness Scotland, in right-hand-drive (that I only had 2 days of experience with) in full rush-hour was pretty fun.

Just adding to the already rich discussion an anecdote about stop signs preceeding a round-about: worst of both worlds.<p>Example: <a href="https:&#x2F;&#x2F;www.reddit.com&#x2F;r&#x2F;bayarea&#x2F;comments&#x2F;10pihgk&#x2F;roundabouts_with_stop_signs_why_is_this_a_thing&#x2F;" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.reddit.com&#x2F;r&#x2F;bayarea&#x2F;comments&#x2F;10pihgk&#x2F;roundabout...</a>

Yet the most dangerous intersection in the county was the only one with roundabouts.

Two-lane roundabouts still confuse me a bit. Even the video tutorial in that article has what looks like a problem to me. At 1:06, the pink car in the right lane skips the first exit. How does the orange car in the left lane know it&#x27;s safe to take the second exit? That&#x27;s a collision risk right there if the pink car wants to continue counter-clockwise.

The authors have never driven in Boston. I grew up and learned to drive there. It is literally the scariest traffic feature of Boston. If you go in a roundabout (or rotary as we call them), you need a will prepared (and it&#x27;s a good idea to have hugged as many relatives as possible beforehand).

safety? bah! try going round the hanger lane gyratory system (west london, uk) in a triumph spitfire, at high speed, driven by a girl (my girlfriend at the time) who was too tiny to reach the pedals.

The _main_ rules are rather simple:<p>- Slow the fuck down<p>- Slow the fuck down<p>- Expect--and tolerate--others to make mistakes

Roundabouts turn into absolute shit shows when backed up.<p>The end.

Obligatory reference to this: <a href="https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Magic_Roundabout_(Hemel_Hempstead)" rel="nofollow noreferrer">https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Magic_Roundabout_(Hemel_Hemp...</a><p>Roundabout with more roundabouts on it. Because.<p>Basically just a little ring road.

Seriously, americans need to learn about these.

Seattle roundabouts are absurd - they’re actually not roundabouts despite being shaped like them, but are traffic slow down artifacts. But people insist on treating them like roundabouts despite being too tight a radius for some cars and the city advising to not treat them as such.

This article makes it sound like traffic lights are more common than roundabouts in the US. In Australia, in most small to mid-sized towns I&#x27;ve been to, roundabouts seem to be much more common than traffic lights. Traffic lights are mostly used in densely populated areas (e.g. town&#x2F;city centers) because roundabouts take up more space.

I’m an Australian who has spent a number of years living in the US, and to be honest I’m not sure roundabouts are that great anymore.<p>Roundabouts might be more efficient for pushing cars through an intersection, but they’re less pedestrian-friendly. Yes that’s right, in this specific case, American cities are more pedestrian friendly than Australian and European cities. At best, a pedestrian has to take an awkward circular detour with a roundabout, and most Australian roundabouts DON’T have a zebra crossing like the picture in the article - so unlike a four way stop, pedestrians don’t have the right of way. If they did, it would likely destroy a lot of the (car-only) efficiency gains in busy areas.<p>The other benefit of the four way stop is that every American just knows what to do when the traffic lights fail, since the rules fall back to the four way stop rules. In Australia, this can be a very dangerous situation until the cops arrive to direct traffic.<p>(For the Australians who don’t know how to navigate a four way stop: you arrive at an intersection where all four entrances have a stop sign, so you stop, and then go through in the order that you arrived)