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Safety benefits of roundabouts

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Re: Safety benefits of roundabouts

#381

Post by globular-toast »

iggldiggl wrote: post #374
vinay427 wrote: post #315

Earlier quoted context omitted.

> Then again I’m in a country where drivers are generally respectful of pedestrians, especially on marked crossings most drivers will actively stop if they see a pedestrian getting close to a crossing. This seems to not generally be the case in the UK, or at least in any of the large and small cities in England that I’ve spent time in. Except for zebra crossings (which are few and far between at crossings compared to…

For a long time the UK had a rule whereby turning traffic only had to yield to parallel pedestrians already crossing the street. Only relatively recently did the rule change to turning road traffic having to yield to all pedestrians walking alongside, even if they're only about to start crossing. Coming from Germany, that difference in rules was always noticeable when going on a vacation to the UK.

Amazingly it didn't even apply to cyclists on the road either (ie. a motorist could overtake and immediately turn left in their path). The new rules explicitly establish a hierarchy of road users with motorists at the bottom: lowest priority, highest responsibility.

It takes a long time for cultural change to happen, though. We have multiple generations of entitled motorists on the road at this point. And a carbrained prime minister.

Re: Safety benefits of roundabouts

#382

Post by whycome »

kieranmaine wrote: post #91
swatcoder wrote: post #45

Earlier quoted context omitted.

Yes, they're absolutely horrid for pedestrians. Drivers anticipating their merge into roundabout are often too distracted to notice pedestrians intending to cross, and any pedestrian crossing the outflow of a roundabout can trigger a traffic backup that interferes with the flow of the circle itself and surprise drivers who expect it to stay moving. They have their benefits in some intersections, but they also have tr…

I disagree. As a pedestrian, I only have to worry about cars coming from 2 directions (on to/off the roundabout) instead of 4 at an intersection. I'm confused by your comment that drivers merging into a roundabout are too distracted. As a driver merging into a roundabout I find I have far less cognitive load. I only have to look for pedestrians crossing in front of me and cars coming from the left. When coming off th…

> As a driver merging into a roundabout I find I have far less cognitive load.

What I've seen first hand in Ontario/Canada is that there's a huge increase in cognitive load simply because the roundabouts are still fairly new. Most drivers were never taught about them. They've just appeared. And they aren't completely intuitive for many drivers -- so their entry/exit isn't always ideal/safe.

Re: Safety benefits of roundabouts

#383

Post by kimixa »

yreg wrote: post #140
smeej wrote: post #135

Earlier quoted context omitted.

I think you're right about single vs. 2+ lanes. It doesn't matter how many diagram signs they put up before the roundabout entry, people will NOT understand a roundabout with more than one lane, and under no circumstance will people going straight through realize they have to yield to someone coming from the opposite side who's going 270° around the circle and exiting from the inner lane. Roundabouts are fine if the…

> people will NOT understand a roundabout with more than one lane We have tons of 2-lane ones and everyone understands them…

There's lots of multi-lane roundabouts in the UK, and generally seem to work well, but they're often inconsistent with how lanes merge or depart.

One that gets me every time I go past is one where there's like 20 signs saying that both lanes continue to the main road to the right (270 degrees around, the UK so driving on the left), but I don't think I've ever been through there and not have someone try to merge in to me trying to get into the left lane to exit, despite both lanes leading to that exit.

Re: Safety benefits of roundabouts

#384

Post by sagarm »

buro9 wrote: post #266

Swindon, UK would like to remind the World that recursive roundabouts are a thing too. https://i.imgur.com/4pMhdMl.gif

I'm not surprised that pedestrians are waiting to cross rather than taking right of way at an abomination like that. With driver load that high it would be suicidal, whether or not they legally have right of way.

Re: Safety benefits of roundabouts

#385

Post by JohnFen »

smeej wrote: post #135
Enginerrrd wrote: post #107

Earlier quoted context omitted.

Transportation engineer here: Multi-lane roundabouts don't typically have any safety benefits. Single lane roundabouts do. Also, on the small side where you have traffic circles rather than roundabouts, those also suck.

I think you're right about single vs. 2+ lanes. It doesn't matter how many diagram signs they put up before the roundabout entry, people will NOT understand a roundabout with more than one lane, and under no circumstance will people going straight through realize they have to yield to someone coming from the opposite side who's going 270° around the circle and exiting from the inner lane. Roundabouts are fine if the…

> It doesn't matter how many diagram signs they put up before the roundabout entry

It doesn't help that often those signs are pretty confusing all by themselves (at least the ones I've seen), and can't really be grokked from a brief glance driving by.

It would be better if all such roundabouts were consistent in how you should navigate them, but that isn't the case in my area.

Re: Safety benefits of roundabouts

#386

Post by JohnFen »

yreg wrote: post #339
dagw wrote: post #310

Earlier quoted context omitted.

Where are you? We have tons of 2-lane roundabouts in Sweden as well, and I can assure you that far from everyone understands them. And even if they understand them in the sense that they got the theory question about them correct on their driving test, everybody certainly doesn't implement that knowledge consistently and correctly when faced with a 2-lane roundabout.

Bratislava, Slovakia. I don’t recall anyone I know having an accident on a roundabout. Newbie drivers I talk to/drive with are much more worried/unsure about crossings (both the ones without traffic lights and the big ones with many lanes) and of course about parking. Of course, there will be SOME people who are clueless on roundabouts, similar to how there are always some people who will stop on a highway after miss…

> there are always some people who will stop on a highway after missing an exit and pull back.

What?? People do that??

My mind is blown. I've never once seen that happen, so the possibility never entered my mind. Now that I think about it, though, I should probably be more surprised that I haven't encountered it.

Re: Safety benefits of roundabouts

#387

Post by bonton89 »

Fatnino wrote: post #376
moribvndvs wrote: post #373

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. There are two roundabouts near me. The same two problems are rampant. 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 s…

Stanford University has been installing roundabouts in recent years. But they put pedestrian cross walks across all the entrances and exits. So you find yourself driving around and come across a car fully stopped in the loop because some kid is crossing the exit on foot.

We had a roundabout like that with stop lights in the middle for the crosswalks, although I think the crosswalks were later removed and rerouted foot traffic elsehwere. I felt like everyone was complaining people didn't know how to use it but it seemed obvious to me the designers didn't understand the concept either. The crosswalks seemed to exist so the center green could be used a part. I'm not sure how many people enjoy sitting in a part literally surrounded by exhaust fumes and road noise.

The same roundabout has double lanes for only half of the circle so if you are not familiar with it you may find yourself forced to exit suddenly at a turn you didn't want because the lane stops existing. My understand was the point of a roundabout was that traffic always kept moving inside them and you shouldn't stress if you miss the turn because you can just go around the circle to try again.

Re: Safety benefits of roundabouts

#388

Post by kazinator »

autoexec wrote: post #275
kazinator wrote: post #172

Earlier quoted context omitted.

All roundabouts prevent vehicles from just blowing straight through the intersection in the desired direction without so much as slowing down. They remove the middle part of the intersection where conflicting paths intersect. Two-lane roundabouts are larger; cars go around them faster. There is ambiguity. Some cars short-cut using the middle lane, and veer right out of it to their desired exit. Cars in the outer lane…

> I don't think these situations will typically lead to anything worse than fender benders. Since even a fender bender can cost many thousands of dollars in repairs that's still pretty terrible. Speed bumps slow drivers down too and don't risk people turning into you because they were trying to exit from the inside lane of a roundabout.

s/because they were trying to exit from the inside/you were trying to outrace them in the outside lane/

The two lanes are there in larger, busier roundabouts to reduce collisions, not for "slower traffic, keep right"; it's not a freeway. Cars enter the outer lane, and may use the inside lane to avoid other cars entering.

Re: Safety benefits of roundabouts

#389

Post by ClumsyPilot »

philwelch wrote: post #324
ClumsyPilot wrote: post #304

Earlier quoted context omitted.

underpasses should be built for cars, not people. I have recently tried navigating the world, temporarily, with a mobility imparement, and boy does it change your perspective on things. Why do I, as a pedestrian, have to go down and then back up, why is the guy sitting in a box with 200 horsepower not the one going up and down? Also car underpasses do not become a public toilet the way pedestrian ones do Why are able…

> Why does a train station in the middle of a spacious suburb have no elevator, no ramp, and no way to get out if your can't use stairs? As an American it’s often surprising to me how many countries lack any analog to the Americans with Disabilities Act.

They do, the station is just 100 years old and the act does not force them to upgrade old infrastructure.

There is a clear difference between how quickly infrastructure for cars gets fixed, and how a simple ramp could be not installed at a train station for decades.

Re: Safety benefits of roundabouts

#390

Post by peeters »

sfn42 wrote: post #259
RHSeeger wrote: post #222

Earlier quoted context omitted.

Honestly, even looking at a picture showing how a 2-lane roundabout works ( https://www.epermittest.com/drivers-education/roundabouts ), I still can't understand how it works. Assuming 0 is the bottom and 90 is the right, how is it that a person following the inside route from 0 (exiting the left lane at 180) isn't going to get hit by someone following the outside route from 90 (exiting the right lane at 270)? I woul…

The part you're missing is you have to yield when changing lanes, just like in any other road. If you are in the inner lane and you want to exit, you have to make sure the coast is clear. In other words, you are responsible for not getting hit. If you just blindly change lanes you might get crashed into and that would be your fault.

> The part you're missing is you have to yield when changing lanes, just like in any other road.

This is not true with most roundabouts in North America at least. If you look at the diagram GP posted, you do not change to the outer lane to exit. You exit directly from the inner lane. In fact, you NEVER change lanes in a roundabout. The reason this works (where the inside lane crosses the outside) is because the roundabout is small enough that the traffic in the outside lane has to let you exit as part of yielding to enter the roundabout in the first place. After that, as long as everyone respects which exits they're allowed to take from which lane, there is no more crossing traffic. In practice, if you are in an inside lane, you want to keep an eye on the outer lanes to make sure someone isn't trying to take a later exit than they are allowed.

From GP link:

> Do not change lanes in a roundabout

> Do not travel in the outside lane further than allowed as it may create a hazard for the vehicle exiting the roundabout from the inside lane

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