We're excited about our new roundabout • Hacker News Board

Re: We're excited about our new roundabout

#171

Post by DrBazza » Mon, Oct 07, 2024, 10:09 AM UTC

Auracle wrote: post #128

bnralt wrote: post #95

Earlier quoted context omitted.

Online I see this mentality that roundabouts are great no matter what and it seems really strange to me. It really depends on the design of the roundabout and the traffic conditions. Where I grew up there are a lot of roundabouts, but many of them are so dangerously designed I started actively avoiding them. It’s not that you can’t poorly design a four way stop, but it seems to be much less common, for whatever reaso…

My experience driving in rural France was that nearly every intersection was a roundabout and it slowed things down dramatically. Many, many times I was the only driver within sight. Surely one of the two directions is more used and a couple of putting stop signs the other way would make more sense. Roundabouts are great sometimes, but they aren’t a magic bullet. That said we have a nasty intersection in the area on…

Try driving in England, rural or otherwise, and you'll see our current trend of adding traffic lights to roundabouts.

If you think roundabouts slow you down (they don't really), just wait until non-rush hour at one of these "roundabouts" when you're the only car waiting on several sets of red lights, or during rush hour when the lights have failed and it's totally gridlocked where traffic simply cannot pass.

Re: We're excited about our new roundabout

#172

Post by esskay » Mon, Oct 07, 2024, 10:10 AM UTC

alt227 wrote: post #164

jen729w wrote: post #157

Earlier quoted context omitted.

Similarly this is a mandatory mention. https://en.wikipedia.org/wiki/Magic_Roundabout_(Hemel_Hempst...

Oh come on the Swindon one is the original and best :) https://en.wikipedia.org/wiki/Magic_Roundabout_(Swindon)

Hemel's is much more fun to drive around though, it's bigger and has the traditional lack of signage and faded lines as a bit of an extra challenge.

Re: We're excited about our new roundabout

#173

Post by DrBazza » Mon, Oct 07, 2024, 10:11 AM UTC

maltalex wrote: post #88

woleium wrote: post #77

Earlier quoted context omitted.

In the UK they are called mini roundabouts, and are sometimes just painted on: https://commons.m.wikimedia.org/wiki/File:Mini-roundabout.jp...

Painted roundabouts will be invisible when it snows.

The signs preceding a UK mini roundabout would not be.

And it rarely snows in the UK these days. And I would hope you would be driving extremely cautiously if there were snow on the ground (in the UK) as it's such a rare event.

Re: We're excited about our new roundabout

#174

Post by esskay » Mon, Oct 07, 2024, 10:13 AM UTC

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/

Nobody in their right mind would ever class that as a roundabout. You dont stick a high speed road directly through a roundabout.

An actual roundabout DOES solve the tbone issue.

Re: We're excited about our new roundabout

#175

Post by esskay » Mon, Oct 07, 2024, 10:15 AM UTC

lozenge wrote: post #167

Aeolun wrote: post #124

Earlier quoted context omitted.

What should I imagine when you say roundabout with 4 stops? Isn’t that just an intersection that looks like a roundabout without functioning like one (entirely negating the point)?

I guess drivers just don't realise they need to slow down or give way to anybody unless there's a stop sign, traffic light or they're turning into a different road.

Surely drivers know what Yield means though right? I guess the US might need yield signs at a roundabout given not all drivers will get the basics of how they work. There should never be a stop sign on a roundabout, the whole point is you're supposed to be able to keep going without stopping at all if theres nobody coming round it.

Re: We're excited about our new roundabout

#176

Post by esskay » Mon, Oct 07, 2024, 10:17 AM UTC

maltalex wrote: post #88

woleium wrote: post #77

Earlier quoted context omitted.

In the UK they are called mini roundabouts, and are sometimes just painted on: https://commons.m.wikimedia.org/wiki/File:Mini-roundabout.jp...

Painted roundabouts will be invisible when it snows.

Signage exists. Plus the vast majority of times painted ones are used in areas where almost everyone on the road knows how it works, and within minutes of it snowing a very clear outline of the path cars have taken would make it abundantly clear what the process is.

Roundabouts are engrained into UK road culture, you'd seldom find a driver in the UK that cant figure out how one works, even if they may not have great lane discipline on the larger ones.

Re: We're excited about our new roundabout

#177

Post by offices » Mon, Oct 07, 2024, 10:20 AM UTC

tda wrote: post #168

asib wrote: post #165

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This is literally just how you're supposed to go round any roundabout. Right lane if you're going straight ahead or right (to any extent), left lane otherwise. Anything else _will_ cause crashes, because vehicles will necessarily have to cut across each other to exit the roundabout. The "turbo roundabout" might make this explicit, but it's not different.

It's only the difference between CI enforcing code style vs manual PR reviews that have a checkbox for code style. They accomplish the same, but one is infinitely better.

It seems this would solve the problem with normal roundabouts where you have a lane you should be following but know that a vehicle in an adjacent lane is likely to infringe on yours.

Re: We're excited about our new roundabout

#178

Post by ifwinterco » Mon, Oct 07, 2024, 10:21 AM UTC

Plasmoid2000ad wrote: post #170

fransje26 wrote: post #154

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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-…

Roundabouts with traffic lights are a bit of a failure alright - and the larger ones are i'd argue not roundabouts at all - they just share the shape. I believe traffic lights are always trying to solve a capacity issue - where the roundabout has hit it's maximum capacity and is suffering some throughput issue, which tend to sort of get exponentially worse. With traffic light sequencing, particularily dynamically, th…

The issue that can happen is when one direction has significantly more flow than the other - in this case you end up needing traffic lights otherwise nobody can ever pull out from the minor direction at rush hour.

The other issue in the UK is massive signalised roundabouts used for junctions where traffic volumes clearly justify a proper grade separated junction like a stack, purely to penny pinch. South Mimms A1M/M25 junction is a good example, or the M2/M25 junction where they eventually had to put in free flowing slips eastbound to northbound because the roundabout was constantly congested.

That's not really a problem with roundabouts per se though, it's just bad design choosing an inappropriate junction design purely to avoid having to pay for bridges

Re: We're excited about our new roundabout

#179

Post by lupusreal » Mon, Oct 07, 2024, 10:21 AM UTC

asib wrote: post #163

necrobrit wrote: post #149

Earlier quoted context omitted.

The preference for 4 way stops in a country that otherwise prioritises traffic flow so much is really jarring. Traffic lights too to some extent. About 5 years ago my wife an I were doing a California road trip. At one point on a relatively rural road -- I think it might have been Dry Creek road heading into Napa but cannae mind exactly -- we got stuck in traffic for around 45 minutes. We thought there must have been…

4-way stops are bizarre to me having grown up in the UK where roundabouts/intersections with priority given for one direction are trusted and reliable traffic-calming measures. I think one of the reasons a 4-way stop might be introduced is to improve safety where there was previously a 2-way stop (that people would blow through). I came across this in Canada recently. All I can say is the UK has drastically lower tra…

Four way stops are common in lightly trafficked situations where the locals can't justify spending the money on anything but a few stop signs. For instance, the main street through a small town (Four way stops are also common when two country roads of relatively equal weight intersect. There are so many roads like that, so many intersections, that the local government can't possibly afford lights or circles on all of them. If one of the roads is known to get substantially more traffic than the other than a two-way stop is usually used, but if it isn't obvious then a four way stop is the safe default. In these situations, pedestrians aren't a factor at all because the intersection is five miles away from a town and it's farmland on both sides of both roads. Virtually nobody is walking there, not even people walking their dogs (unpaved access roads are better for that anyway.)

Re: We're excited about our new roundabout

#180

Post by esskay » Mon, Oct 07, 2024, 10:22 AM UTC

buildsjets wrote: post #104

bigstrat2003 wrote: post #93

Earlier quoted context omitted.

> Half the time the only way you can tell it’s an all way stop is by looking for the back of the stop signs on the perpendicular road. Your state is doing it wrong then. Almost every four way stop I've ever seen in the US has a little sign beneath the big octagon which says "4-way". Anyways, I have nothing against roundabouts. But I do have issue with some states (looking at you, Wisconsin) which are obsessed with te…

My elderly father will go 20 mins out of his way to avoid this series of intersections in Oshkosh: https://maps.app.goo.gl/5SiJhyQREhNSN8PJ9

I do love how on streetview they've caught what looks to be an accident on it: https://www.google.com/maps/@44.0108294,-88.5835298,3a,75y,5...

That being said that looks like a pretty decent and standard setup for a set of roundabouts, certainly wouldn't look out of place in the UK and would be vastly superior to a whole host of stop signs and red lights. It probably could've been simplified slightly by turning the two middle ones into one long oval roundabout, those are pretty common on motorway junctions in the UK.