When I first came here they usually had three lanes, with the idea that you change lanes as you move through the roundabout - this meant almost daily you would see a minor RTI on a roundabout, which would cause large queues of traffic. Some roundabouts also had three lanes where you enter and exit, but they were usually signalled.
A few years ago they reduced the roundabouts to two lanes, and all exits to one lane. The idea being that for the first and second exit you need to use the outer lane, and for the third or fourth exit you use the inner lane. That inner lane becomes the outer lane after the second exit, so you just stick to the same lane once on the roundabout. The only time you need to change lanes is if you miss your exit and need to go around again. There are clear signs before you reach the roundabout saying which lane you need for which exit.
Since this change was made, I think I've seen maybe one RTI on a roundabout - when somebody was being stupid and tried to overtake a bus. It's such a simple change, but it's crazy how effective it has been. They've also started adding speed bumps to some roundabouts to slow traffic, which actually increases capacity as it's easier to join with slow moving traffic.
From a quick search, I think it's British. As an American, I'd never encountered either the acronym or the expanded form.
The main problems IMO are:
- you can just go around again if you aren't sure which exit you need; you are forced into taking an exit, right or wrong
- the radius is too small so there is not much time to make a complex decision, especially if you aren't already familiar with the exits
- it's hard to monitor traffic entering the roundabout to make sure I don't get hit by someone having a harder time navigating this than me, while at the same time trying to figure out what the crazy sign diagrams mean.
- there's no confirmation when you do take an exit that you've taken the right one. Might not be a road sign for 10-15 seconds, which is a long time when you're not sure where you're going.
- they're even worse at night because there's not enough lighting. Not too bad for the exits toward civilization, but pretty confusing for the more rustic ones.
I think the idea is okay, but at least for the ones they put in here, the execution is not so hot.
There are then large signs at every exit on the roundabout.
Sometimes (not here) the approach lanes have giant letters/numbers painted in each lane, even if it's crushed so Warwick is written "Wa'ck" or something.
Nothing prevents you going around a second time if you need to. Your satnav will have said something like "In 500m, at the roundabout, take the second exit to Warwick" and then "Take the second exit to Warwick".
On this road (which is typical) there's the confirmation-of-route sign very soon after exiting the roundabout towards Warwick, or (third exit) to the village.
> you can just go around again if you aren't sure which exit you need; you are forced into taking an exit, right or wrong
...doesn't make sense?
> the radius is too small so there is not much time to make a complex decision, especially if you aren't already familiar with the exits
Ideally, you should know what exit you need from the signs you saw approaching the roundabout. If not, slow down and go around again.
> it's hard to monitor traffic entering the roundabout to make sure I don't get hit by someone having a harder time navigating this than me, while at the same time trying to figure out what the crazy sign diagrams mean.
This is why the signs were 100-200m before the roundabout. It sounds like you are approaching the roundabout too fast.
[1] https://www.google.com/maps/@52.1980889,-1.6002025,3a,75y,23...
This is a common problem with USA roundabouts. People think of them like a freeway on-ramp and traffic engineers do nothing to calm the traffic entering. So people go through them as fast as possible. Slowing down in a roundabout tends to piss off a lot of folks who think they should be doing highway speeds.
> ...doesn't make sense?
It's supposed to be "you can't just...", it also means your solution of slowing down and going around again doesn't work.
When we're not sure that we're about to come off at the right exit, we just go around again. I find myself doing this in unfamiliar places occasionally.
Not sure what your first point is saying, but the fact you can just go around again until you're sure you're going the right way is a great feature, IME.
I think the reason that introducing roundabouts somewhere where people aren't used to dealing with them all the time is ... well, just that. There needs to be enough of them for people to be comfortable with the right way to approach them - and not just them, but others using them, before they work as intended.
In summary: Roundabouts are a really good way of managing a junction, but - like most road features - they need to get to a point of being familiar to most road users before they're as effective as they can be.
On there other hand they have a maximum throughput and that can only be alleviated by an interchange --even modest ones.
It's a variant of the "when you only have a hammer" analogy: when you first learn how great a hammer can be, everything looks like a nail.
At least I think so, they might be complaining that you aren't forced to take an exit.
> Roundabouts are not traffic circles. Roundabouts follow a yield at entry rule, which requires approaching vehicles to wait for a gap in the circulating traffic before entering the roundabout. Roundabouts involve low speeds for traffic entering and driving through the roundabout; they use deflection to slow entering traffic and enhance safety. Vehicles in the roundabout have the right of way.
> Another distinguishing difference between traffic circles and roundabouts is that roundabouts have a smaller diameter than most traffic circles, resulting in safer conditions and lower speeds. Vehicles can enter modern roundabouts much easier than traffic circles due to flared approaches, entry angles, slower speeds on the circulating roadway and the fact that vehicles entering roundabouts always yield to circulating traffic.
> Entering a roundabout is as easy as making a right hand turn onto a one-way street.
One funny story my wife told me was, she was once a passenger in a car driven by someone unfamiliar with roundabouts. Upon encountering their first one, they proceeded to drive round and round, afraid to exit.
The unfortunate truth, is that because there are so few roundabouts here, driving schools do not make it part of their curriculum.
Chicken, meet egg.
However, I am a firm believer in roundabouts. Ignorance is a poor justification for continuing to build four-way intersections in places that do not require them.
I think this is pretty much a constant in road security, where putting more stress and forcing the driver to pay attention leads to overall better outputs (enforced road bumps, sound inducing road sides, fake people display on crossing paths etc.)
PS: on people not yielding, speed are lower than on straight lines so it's still less problematic than usual non yielding. But I hope your neighbors will get used to roundabouts and navigate them better.
https://cyclingincities-spph.sites.olt.ubc.ca/files/2018/06/...
At least with a standard crossing intersection of say the E->W road is hosed up because of a traffic accident the other flows of traffic are unaffected as long as the intersection remains clear. Even if some jerk gets stuck in the middle they have the ability to U turn out to unblock the intersection.
With a roundabout when it's not clogged its very nice and I do enjoy them. But I've also been stuck at an intersection for more than an hour because of a fender bender in a roundabout causing a full traffic stoppage with no way out.
Problem is if people are used to them they work well but if you rarely see them people don’t really understand the concept and just kind of blast through them without yielding.
Almost got taken out a few times when I was a cabbie, people just go full speed into them without looking.
The new hotness seems to be intersections where the traffic crosses over to the other side and left turns are uncontested(?).
(un)friendly reminder that this goes for the people in the city plannign department first and foremost.
You can't just dump one in at every intersection and expect them to work out. It only works out when there's similiar traffic volumes on the intersecting streets.
Of course people just drive on through when the volumes are such that that's the prevailing flow.
Not that I have anything against 2-way stops but that's basically what you create a lot of when you start carpet bombing your town with roundabouts because they're trendy.
Since the "circle" is so small, you yield to approaching vehicles on the junction, but also to a vehicle waiting at the entrance to your right¹, i.e. the vehicle that is waiting in the direction you're looking in anyway for traffic on the "circle".
If there are no other cars, you barely need to slow down.
In most cases, even if the junction is busy, a car trying to enter from an uncommon direction will quickly be able to go as someone in the main direction will need to yield.
¹ Driving on the left in Britain, of course.
Diverging diamond interchange[1]?
[1]: https://en.wikipedia.org/wiki/Diverging_diamond_interchange
Head-of-line blocking, where left turns can block through traffic or through traffic can block a left turn lane, is a particularly irritating feature of traditional intersections.
My favorite is Newton Corner, 3-4 lanes of chaos in a 1/2 mile circumference featuring 200+ street signs, 23 crosswalks, 12 traffic lights, intersecting 6 local roads, and a highway interchange. Oh, there's also a couple bus stops for the 10 or so bus routes. One is generally required to cross several lanes of traffic to exit the rotary at the desired location.
The roundabouts that have popped up are downright relaxing in comparison.
https://podcasts.apple.com/us/podcast/should-traffic-lights-...
Rotaries on the other hand are super-confusing and an aberration in the history of traffic management.
