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Safety benefits of roundabouts

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Re: Safety benefits of roundabouts

#51

Post by SoftTalker »

hristov wrote: post #20

The greatest thing about roundabouts is that they protect against the idiot that goes through an intersection at full speed. He does that either because he is passed out behind the wheel or because he did not notice a stop sign and thought he had the right of way, or maybe because he just does not care. Well with a roundabout if you just go straight ahead you hit the center circle. Good roundabouts always have a slig…

I knew a guy who didn't stop at all-way stop signs. His thinking was: if everyone else is going to stop, why should I?

Re: Safety benefits of roundabouts

#52

Post by kridsdale3 »

123pie123 wrote: post #39
hristov wrote: post #20

The greatest thing about roundabouts is that they protect against the idiot that goes through an intersection at full speed. He does that either because he is passed out behind the wheel or because he did not notice a stop sign and thought he had the right of way, or maybe because he just does not care. Well with a roundabout if you just go straight ahead you hit the center circle. Good roundabouts always have a slig…

there's a few videos if you look, this one was popular https://www.youtube.com/watch?v=xTk_kPeA63c

That is the worst audio waveform I have ever been subjected to.

Re: Safety benefits of roundabouts

#53

Post by _zamorano_ »

In Spain we use roundabouts heavily.

They're perfect for crossings with low to middle traffic. No useless waiting time, good visiblity and no need for traffic lights.

For heavy traffic, though, they're useless as the car flow of one entry/exit can take over the roundabout and block all other entries.

Also, it seems hard to understand for many drivers that regulations regarding changing lanes don't change in a roundabout. So more than 3 lanes are not advisable in my opinion.

Re: Safety benefits of roundabouts

#54

Post by eesmith »

spogbiper wrote: post #3
tpmx wrote: post #2

Seriously, americans need to learn about these.

we have tons of them where i live in south florida

There are differences between a modern roundabout and the broader category of circular junction.

The De Soto Plaza in in Coral Gables, FL, built in 1925, as seen at https://www.google.com/maps/@25.7450124,-80.275242,3a,75y,75... is not a modern roundabout. Granada Blvd does not indicate a yield-to-enter, while the others streets have stop signs.

I think that one should also have splitter islands.

(Video of its history at https://archive.org/details/Did_You_Know_-_DeSoto_Plaza_Foun... .)

I think Cocoplum Circle might count as a roundabout? https://www.google.com/maps/@25.7059315,-80.2608362,3a,75y,1...

There are also "traffic calming circles", which are not roundabouts. "Traffic calming circles should not be confused with roundabouts, which are designed to handle much higher traffic volumes and reduce vehicle delay." - https://www.sfbetterstreets.org/find-project-types/pedestria...

Re: Safety benefits of roundabouts

#55

Post by DavidVoid »

hristov wrote: post #20

The greatest thing about roundabouts is that they protect against the idiot that goes through an intersection at full speed. He does that either because he is passed out behind the wheel or because he did not notice a stop sign and thought he had the right of way, or maybe because he just does not care. Well with a roundabout if you just go straight ahead you hit the center circle. Good roundabouts always have a slig…

> they include rather obscure rules as to which lane you are allowed to drive in at any moment and americans do not like to learn new rules.

Do they? I guess it probably depends on the country. Here in Sweden I'm pretty sure you can drive in whatever lane you like (unless they're explicitly labeled). But normal lane-swithching rules apply ofc and, importantly, when you enter a roundabout you have to yield to traffic in all lanes of the roundabout, not just the outermost one.

Re: Safety benefits of roundabouts

#57

Post by giantg2 »

calimoro78 wrote: post #10

My experience is that roundabouts help but don't solve. E.g. if there is a complete traffic jam, you may actually increase the risk of collision due to negotiations about right of way happening every time a car can move forward. Some cities in Europe have so many roundabouts, and two or three lane roundabouts with complex exit decisions you need to make on a split second - it's actually very confusing to navigate.

"My experience is that roundabouts help but don't solve"

Because they don't remove the idiots from the roads. The same people who willfully ignore right of way at stops signs also ignore right of way in the roundabout.

Re: Safety benefits of roundabouts

#58

Post by KaiserPro »

calimoro78 wrote: post #10

My experience is that roundabouts help but don't solve. E.g. if there is a complete traffic jam, you may actually increase the risk of collision due to negotiations about right of way happening every time a car can move forward. Some cities in Europe have so many roundabouts, and two or three lane roundabouts with complex exit decisions you need to make on a split second - it's actually very confusing to navigate.

> My experience is that roundabouts help but don't solve. E.g. if there is a complete traffic jam

Agree, when at or near 100% utilisation, its slower than a normal junction.

> you may actually increase the risk of collision due to negotiations about right of way happening every time a car can move forward.

That shouldn't be the case. Ideally you should always have priority from one direction (like in the UK, germany and the netherlands.) The generally rule is that when you come to the round about, if you see someone on your right(in the UK, left everywhere else I imagine) you stop and wait for them to drive past.

> two or three lane roundabouts with complex exit decisions you need to make on a split second

The driving exam will test you for this in the EU. The lane you chose is directly related to where you need to exit. If you are going straight over, or less, then its the outer most lane. Anything more than 180 degrees you take the inner lane. Exceptions will be clearly marked in both floor markings and signs well before entry.

Re: Safety benefits of roundabouts

#59

Post by giantg2 »

dfxm12 wrote: post #30
calimoro78 wrote: post #10

My experience is that roundabouts help but don't solve. E.g. if there is a complete traffic jam, you may actually increase the risk of collision due to negotiations about right of way happening every time a car can move forward. Some cities in Europe have so many roundabouts, and two or three lane roundabouts with complex exit decisions you need to make on a split second - it's actually very confusing to navigate.

You're never going to "solve" traffic problems when people are driving cars, but when you look at the data, crashes that lead to injuries and, importantly, fatalities, go down with roundabouts. and two or three lane roundabouts with complex exit decisions you need to make on a split second - it's actually very confusing to navigate. I think you're confusing what today might be called a "rotary" (?) with a modern roun…

I've seen 2 lane roundabouts brand new in the US.

Re: Safety benefits of roundabouts

#60

Post by marginalia_nu »

Arrath wrote: post #42
marginalia_nu wrote: post #28

Earlier quoted context omitted.

Using roundabouts of roundabouts it's actually possible to build a 3 dimensional roundabout where traffic along the x, y and z axis can safely meet on the surface of a sphere.

Please, the average driver has trouble enough merging into traffic.

Well, when you mention it, I do think it's possible to join these 3d roundabouts into a 4d roundabout, essentially putting them on the vertices of a tesseract, permitting drivers in 4 dimensional space to safely meet on the 3d-dimensional surface of a 4-dimensional hyper-sphere.

Of course it's a real spaghetti intersection where you need to potentially navigate dozens of 2D roundabouts to get to any given direction. Which coincidentally also is true for the 2D road network where I live.

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