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Safety benefits of roundabouts

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Re: Safety benefits of roundabouts

#251

Post by globular-toast »

devnull3 wrote: post #68

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] When visiting for the first time on a specific spiral roundabout: 1. Lane markings are faded 2. You do not know the specific lane unless you come very close to it and have to make a quick decision 3. Often due to queued traffic you cannot even see the lane marking until its too…

This is a problem with all multi-lane layouts and exacerbated by drivers' behaviour.

The problem is road users new to the road do not know which lane to be in already and they are pressured to go fast. The instant it looks like they've chosen a lane, a driver from behind who is familiar with the layout closes the gap in the other lane, trapping them.

This can be mitigated a bit by the first user having the confidence to slow down and straddle lanes until they are sure of the correct lane, but it's surprising how quickly such opportunities are missed.

The real problem is familiarity with lane layouts allows the road to operate at far higher capacity then normally possible and with less maintenance. They are squeezed to their limits in morning rush hours comprised of mostly familiar users. You'll even see users observing essentially invisible road markings because they're doing it from memory. No chance of you're unfamiliar with the road. Roads start to fail way before 100% capacity, but these lane markings allow that to be squeezed further during rush hours.

Re: Safety benefits of roundabouts

#252

Post by fifticon »

verve_rat wrote: post #241
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 "correct" answer is the 0->180 car has no indicator on as it enters the roundabout, and has its right indicator on as it exits the roundabout. The 90->270 car sees the right indicator and lets the other car passed. The real answer is somewhere between the above and the 90->270 car waiting to enter the roundabout because it is not sure if the other car is actually going 0->180 or 0->270 because they are a shit div…

well, that breaks all schemes, as my experience in 52 years is, that most people don't or won't operate their indicator signals properly. They seem to believe they are for special holidays, or for a particular audience they have spotted (spoiler alert: they are for the opposite). Or, my favorite: Activating the indicator two thirds of the way through the already completed turn, presumably to celebrate the success.

Re: Safety benefits of roundabouts

#253

Post by michaelt »

occz wrote: post #230
adgjlsfhk1 wrote: post #203

Earlier quoted context omitted.

The lack of lights and increase in number of crossings (for non-tiny ones) make them pretty terrible to cross as a pedestrian.

>The lack of lights and increase in number of crossings (for non-tiny ones) make them pretty terrible to cross as a pedestrian. This can surely be remedied by having the crossings being raised, acting as speed bumps for the cars and providing a better crossing experience for the pedestrian (or cyclist). I'm not entirely convinced that the lack of lights would inherently mean that roundabouts are less safe for pedestr…

Here in the UK, any difficult-to-cross junction will have a roundabout, simply because our road designers love roundabouts.

And for large/busy roundabouts, cars will be in constant motion meaning there won't be gaps in the traffic flow for pedestrians to cross. If you try to cross [1] on foot at a busy period, it's not a particularly fun experience.

Of course, I'm not sure any road layout could make such a junction easy to cross, given the amount of traffic and number of lanes involved.

[1] https://www.google.co.uk/maps/@51.6428928,-0.2553056,17z?ucb...

Re: Safety benefits of roundabouts

#254

Post by generic92034 »

sfn42 wrote: post #240
kdmccormick wrote: post #209

Earlier quoted context omitted.

(Warning: Anecdata) There was a multi-lane roundabout near me with traffic signals and pedestrian crossing signals and all. It was an absolute nightmare to drive through, bike through, or cross on foot. Cars pressured one another to drive aggressively, pedestrians had to wait for walk signals, cars got confused and blew through the crosswalks by accident even when pedestrians had walk signals, bikes were an afterthou…

I never walk out in front of cars until I have made sure they see me. You never know what's going on with that driver.

> I never walk out in front of cars until I have made sure they see me.

Optimist! ;)

Re: Safety benefits of roundabouts

#255

Post by paganel »

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…

Traffic police here in Romania had to actually add some stuff to the legislation that would make 2-lane plus roundabout traffic easier to understand, the reason being that the traffic policemen themselves had conflicting opinions about who had the right of way inside said roundabouts (when changing lanes, for example).

Re: Safety benefits of roundabouts

#256

Post by meheleventyone »

rapnie wrote: post #242

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 s…

All the different rules for roundabout are fun. In the UK you’re expected to filter to the outside leave. In Iceland the person on the inside has priority to leave so you can still enter the roundabout but need to watch for someone already on the inside wanting to leave at your first exit. The rules are similar to the Netherlands in that you either go straight or 3rd exit from the inside and should only go first exit on the outside, although it’s totally possible to carefully go all the way on the outside. I still find the Icelandic system mildly bonkers but not due to the choice stress as it’s usually obvious which lane you need.

Re: Safety benefits of roundabouts

#257

Post by gnosek »

rapnie wrote: post #242

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 s…

If I understand correctly, you mean turbo roundabouts https://www.ms2soft.com/resources/turbo-roundabouts/ ?

If so, IMO they're the best thing that happened to roundabout design ever. You do need to choose a lane before entering but it's similar to how you'd choose a lane on a traditional two-lane roundabout. However, then you don't change lanes while on the roundabout, with ~zero visibility to the other lane while turning in a fairly tight circle.

This may differ across countries but around here you're supposed to: * pick the inner lane unless you're taking the first exit (to the right) * change to the outer lane just before your exit

which is about infinity times more stressful in traffic (you have very little time, it's hard to see the outer lane and the outer lane has right of way). It would work fine if everybody followed the rules but 1. they don't since it's unsafe in a tragedy of the commons sort of way and 2. then you end up with an informal turbo roundabout anyway.

A compromise that's becoming fairly common is a "soft" turbo roundabout where the lanes are divided not by ridges but by solid lines you can't cross only legally, not physically :)

Re: Safety benefits of roundabouts

#258

Post by rapnie »

meheleventyone wrote: post #256
rapnie wrote: post #242

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 s…

All the different rules for roundabout are fun. In the UK you’re expected to filter to the outside leave. In Iceland the person on the inside has priority to leave so you can still enter the roundabout but need to watch for someone already on the inside wanting to leave at your first exit. The rules are similar to the Netherlands in that you either go straight or 3rd exit from the inside and should only go first exit…

Yes. One gets used to the system and then it works okay. That ridge dividing lanes may be there for safety reasons.. but one thing I observed is the anxiety to choose wrongly, and the subsequent road rage when wrong decision was made. Both intoducing to my noob eyes new safety hazards. And then I didn't mention cars that deliberately drive over the ridge.

Re: Safety benefits of roundabouts

#259

Post by sfn42 »

RHSeeger wrote: post #222
yreg wrote: post #140

Earlier quoted context omitted.

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

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.

Re: Safety benefits of roundabouts

#260

Post by rapnie »

gnosek wrote: post #257
rapnie wrote: post #242

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 s…

If I understand correctly, you mean turbo roundabouts https://www.ms2soft.com/resources/turbo-roundabouts/ ? If so, IMO they're the best thing that happened to roundabout design ever. You do need to choose a lane before entering but it's similar to how you'd choose a lane on a traditional two-lane roundabout. However, then you don't change lanes while on the roundabout, with ~zero visibility to the other lane while t…

Thank you for the name. Yes, that design. As I just commented below the stress point shifts to entering the roundabout where people crazily yank their car sideways to be on the proper lane. At all cost avoiding the feeling of having made the wrong choice. Kind of road rage psychology. And anecdotal, YMMV. I think here the soft turbo is a great compromise.
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