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We're excited about our new roundabout

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Re: We're excited about our new roundabout

#181

Post by zarzavat »

fransje26 wrote: post #154
urbandw311er wrote: post #143

UK reader here (we are pretty much 'all in' on roundabouts) I'm reading this and wondering how they'd cope with the 'Magic Roundabout': https://en.wikipedia.org/wiki/Magic_Roundabout_(Hemel_Hempst... Even UK drivers struggle a bit with this one!

As the credited inventors of the modern roundabout, I've always wondered how the UK traffic planners managed to misunderstand their own creation to the point that they come up with such designs.. An other baffling design I've encountered in the UK is a roundabout with traffic lights half-way through.. Wasn't the concept based on removing traffic lights to fluidify traffic..? As a whole, if designers come up with far-…

> An other baffling design I've encountered in the UK is a roundabout with traffic lights half-way through.. Wasn't the concept based on removing traffic lights to fluidify traffic..?

This is indeed a weird one from a US perspective.

The way to think about it is not as a roundabout with traffic lights, but as a light-controlled intersection in the shape of a roundabout.

A roundabout-shaped intersection can handle more variations than a normal intersection, you can have more than 4 roads, or roads entering at odd angles.

As for what the advantage is of having lights on the roundabout as opposed to on the approach, I have no idea.

Re: We're excited about our new roundabout

#182

Post by offices »

shiroiushi wrote: post #161
lmm wrote: post #100

Earlier quoted context omitted.

They absolutely are. Even if they don't prevent all collisions, they turn T-bones into glancing hits and so save a lot of lives. The worst roundabout beats the best 4-way stop any day of the week. Sometimes there really are easy answers.

>Even if they don't prevent all collisions, they turn T-bones into glancing hits No, they don't, at least not in America. When you let American traffic engineers design a roundabout, you get this: https://www.google.com/maps/@38.8643875,-77.2755474,583m/

This reminds me of this oddity in Nottingham:

https://osm.org/go/eu8S4TeKc?way=50459468

(right-hand drive)

Re: We're excited about our new roundabout

#183

Post by esskay »

dave333 wrote: post #53
meowster wrote: post #43

Earlier quoted context omitted.

I imagine you're referring to a simple line drawing (with labels)?

For example - Britain's most notorious roundabout https://www.google.com/maps/@51.5622263,-1.7713205,3a,48.7y,...

Similar with Hemel's: https://www.google.com/maps/@51.7458345,-0.4742799,3a,75y,21...

The map/diagram helps people not familar, the only really complicated thing is making sure you get in the right lane, and keeping an eye on those around you.

Re: We're excited about our new roundabout

#184

Post by Ekaros »

talideon wrote: post #144
davidgay wrote: post #121

Earlier quoted context omitted.

You can actually screw them up: by our house (in California) they replaced a 4-way stop with a roundabout with no signaling on 2 of the ways, and a stop on the other 2. An absolute disaster, as the 2 ways without the stop assumed they had the right of way over people already in the roundabout. After the neighbourhood complained, it's now a roundabout with 4 stops (not ideal, but not dangerous either).

The right solution would've been to remove all the stops. They defeat almost the whole purpose of the roundabout.

I thought the standard for roundabouts is yield sings on all entrances. Not stops, just simple yields...

Re: We're excited about our new roundabout

#185

Post by ifwinterco »

PetitPrince wrote: post #162
OptionOfT wrote: post #130

The biggest problem with roundabouts the main direction can starve the lesser-used entrances. Imagine the main road going North-South, and you're entering via East to go South. Because of never-ending traffic going North-South you just don't get to enter.

You can have several lanes so that the outer one favor going to the nearest exit: https://maps.app.goo.gl/v76ajKvXhzfAdGZ29 Or you can also have dedicated lane that only go to the nearest exit: https://maps.app.goo.gl/1G2cJf1pWrBkEE5b8

Neither of these really solve the problem if you're trying to go anywhere other than the first exit. OP is right, this is an issue with roundabouts and you end up needing traffic lights in this case (at least at peak times)

Re: We're excited about our new roundabout

#186

Post by esskay »

fransje26 wrote: post #154
urbandw311er wrote: post #143

UK reader here (we are pretty much 'all in' on roundabouts) I'm reading this and wondering how they'd cope with the 'Magic Roundabout': https://en.wikipedia.org/wiki/Magic_Roundabout_(Hemel_Hempst... Even UK drivers struggle a bit with this one!

As the credited inventors of the modern roundabout, I've always wondered how the UK traffic planners managed to misunderstand their own creation to the point that they come up with such designs.. An other baffling design I've encountered in the UK is a roundabout with traffic lights half-way through.. Wasn't the concept based on removing traffic lights to fluidify traffic..? As a whole, if designers come up with far-…

Traffic lights are sort of a 'patch' on them. They usually start off without them, they realise theres flow issues that prevent people coming out of one junction, and its going to either be too costly or impractical (space is a massive issue in the uk remember) to switch to something more complex, so lights are used as a permanent stopgap.

One example of where this has been an ongoing issue for decades is the Black Cat Roundabout on the A1 (https://en.wikipedia.org/wiki/Black_Cat_Roundabout). It's gone through numerous changes to improve things, with lights at various points being one of them. Finally now though its being completely redeveloped to a grade-separated junction as traffic has massively outgrown the roundabout.

Re: We're excited about our new roundabout

#187

Post by turboponyy »

davidgay wrote: post #121
lmm wrote: post #100

Earlier quoted context omitted.

They absolutely are. Even if they don't prevent all collisions, they turn T-bones into glancing hits and so save a lot of lives. The worst roundabout beats the best 4-way stop any day of the week. Sometimes there really are easy answers.

You can actually screw them up: by our house (in California) they replaced a 4-way stop with a roundabout with no signaling on 2 of the ways, and a stop on the other 2. An absolute disaster, as the 2 ways without the stop assumed they had the right of way over people already in the roundabout. After the neighbourhood complained, it's now a roundabout with 4 stops (not ideal, but not dangerous either).

This is literally just a skill issue

Re: We're excited about our new roundabout

#188

Post by Karellen »

freditup wrote: post #40

The picture of the roundabout from above at the beginning of the article is extra confusing because it doesn't have the final lane markings yet and the ones you can see are misleading. The (presumably) final markings[0] make things less confusing. [0]: https://www.google.com/maps/place/High+Rock+Rd,+Washington+9...

Ah, thanks for that.

I was looking at the markings that are there, and they made it seem like traffic approaching the roundabout would have priority over traffic already on it.

Re: We're excited about our new roundabout

#189

Post by Karellen »

jayyhu wrote: post #49
freditup wrote: post #40

The picture of the roundabout from above at the beginning of the article is extra confusing because it doesn't have the final lane markings yet and the ones you can see are misleading. The (presumably) final markings[0] make things less confusing. [0]: https://www.google.com/maps/place/High+Rock+Rd,+Washington+9...

They made a video that explains how to navigate the roundabout, and shows what it will actually look like (with yield markings)[1] [1]: https://youtu.be/07_m7HHiZRw

What the hell is that "dump truck with trailer" on a really long connector at 3:50? Is that a thing in some parts? How does that navigate almost any kind of roadway safely?

Re: We're excited about our new roundabout

#190

Post by prmoustache »

eCa wrote: post #169
teractiveodular wrote: post #142

Earlier quoted context omitted.

Citation needed. As a cyclist I prefer roundabouts: they're faster than lights and don't rob my momentum, and they're safer than uncontrolled intersections/4-way stops because all the cars are coming from the same direction. Caveat: this is for simple, single-lane roundabouts. Multi-lane roundabouts are gnarly for cars and worse for cyclists.

In my experience[1], if there’s no bike path roundabouts are better, in particular for left turns. But on a bike path they are usually not much fun, basically requiring negotiating with drivers 270 degrees apart at the same time. My preferred roundabout is separate bikepath that joins the road just before and is a part of the same surface, usually found in bike friendly places. [1] 60000+ km throughout Europe

If you are on the bike path it really depends of the configuration and how large they are. Ideally you want te driver to have completed his entry so that he can focus on the bike lane. Best ones are those that have an elevated bike path that is seen as a speedbump for the drivers: they are forced to slow down and look.
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