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Safety benefits of roundabouts

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Re: Safety benefits of roundabouts

#301

Post by devnull3 »

gvurrdon wrote: post #292
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 one is particularly bad for lane changing: https://www.google.com/maps/@51.7874467,-1.278506,17.57z?ent... Coming out of Oxford on the A4144 there are two lanes; the left lane is for taking the first two turns and the right lane for the remaining three. But, drivers unfamiliar with the layout who haven't seen the markings, or who fancy jumping the queue, will sometimes use the left hand lane to go straight ahead…

Yeah, I never understood why the lane markings are not above the head and in advance instead of on the road.

> drivers unfamiliar with the layout People familiar with the layout drive even when the markings are completely faded. It causes lot of anxiety if you are not familiar. It happened to me once where I was in a wrong lane. I continued on it as it was the most safest thing to do but the next exit was onto a motorway :). I was so angry with myself.

Re: Safety benefits of roundabouts

#302

Post by crote »

annica wrote: post #192

I could see how these have benefits in some cases. There are also drawbacks… the uncertainty of who is yielding (except maybe by AI). What about snow and ice? If you do some searching there are plenty of reasons why you might not want roundabouts.

In most countries traffic already on the roundabout has priority, as is clearly indicated by the presence of yield signs. There is literally zero uncertainty.

Re: Safety benefits of roundabouts

#303

Post by watwut »

lobochrome wrote: post #201
rcpt wrote: post #180

Ctrl+f "pedestrian" Only one result and it's not even about roundabouts. This is how American traffic engineering is done.

Is your argument that roundabouts are bad for pedestrians? If so why?

Personally, I avoid them, because they typically take longer to get across. First, the traffic just seems to be that way - I am never sure where the car inside it is going and whether the driver is noticing me. Second, they tend to be bigger and typically I have to take detour instead of going straight. I find intersections easier to cross. Especially those with traffic light easier to cross.

The worst is when introduction of it means I have to cross multiple crossings instead of one.

Re: Safety benefits of roundabouts

#304

Post by ClumsyPilot »

kubb wrote: post #227
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.

Underpasses completely solve it. For small, low-traffic roundabouts, you just need pedestrian crossings like on a normal intersection, preferably with an isle between the opposing traffic lanes.

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 bodied men waiting in a queue for an elevator?

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?

Re: Safety benefits of roundabouts

#305

Post by watwut »

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…

The big issue is that multi lane roundabout forces the driver to watch too many things at the same time while giving him very small margin of error. If you are not fast with reactions and aggressive enough, you can end sort of trapped in the inner lane and people are afraid to do one more unnecessary round.

And that means everyone has to watch both left and right at the same time while also trying to figure out layout (Will the outer lane force me out when I do not what to? Some roundabouts are like that. Will the inner lane keep me trapped? etc)

Re: Safety benefits of roundabouts

#306

Post by crote »

oldbbsnickname wrote: post #130
hasbot wrote: post #123

What confuses me on roundabouts is the intended speed. Some are very tight and requires slowing down to 15mph and others can handle faster speeds. Rarely is the intended speed marked. A new roundabout in Brevard, NC has a very tight turning radius. There is a sign warning drivers in the outer lane to watch out for tractor trailers who will have to take both lanes to navigate the circle.

Yes, some residential ones are absurd. This one would've been better as a 4-way stop because there's no way to see traffic from all other sides due to the angles and obstructions. https://maps.app.goo.gl/GWoqaxNfVanXLymp6 One went in here where people normally drive 60 mph: https://maps.app.goo.gl/Ugnm36mkeHs2zpu7A On Clark straight through, I would look for approaching traffic from either side or ahead and would cut…

The first one is totally fine. When you're entering the traffic you're driving at about 15-20mph due to the sharp curve forcing you to, so there is plenty of time to look for traffic already on the roundabout coming from your left. With the exception of the signage, I'd say this is a textbook example of a roundabout done well.

The second one is a bit of a mess. The fact that it is physically possible to take them at 60mph means they screwed up the design. They should've used something like slightly raised cobblestone for the hatched area, and they should've used a raised shoulder at the entrance/exit. This roundabout looks like it was designed by someone who has only ever seen it in a textbook, and never actually driven on one.

Re: Safety benefits of roundabouts

#307

Post by pbmonster »

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

How is that a thing? Why not just have a two-lane roundabout with the third lane skipping the roundabout and going to the next exit directly?

Re: Safety benefits of roundabouts

#308

Post by [deleted] »

xen0 wrote: post #276
meheleventyone wrote: post #265

Earlier quoted context omitted.

Do you know the origin of the UK use because that always confused me as it’s obviously wrong from the drivers perspective of the road! My wild guess would be that from the drivers seat you look outside to the fast lane and look across the inside of the car to look to the slow lanes.

The normal terminology for the sides of a car are 'nearside' and 'offside', with the nearside being where the kerb is, offside being where other cars would be. So I would suppose 'inside' and 'outside' were also considered relative to the kerb.

[deleted]

Re: Safety benefits of roundabouts

#309

Post by Moru »

yreg wrote: post #294
Moru wrote: post #206

Earlier quoted context omitted.

Our town has loads of them too, and everyone think they understand them. Still accidents are common because people think it's ok to just go straight through by changing lane to inner and then directly exiting without yielding to the ones crossing their path in the outer lane.

In my country accidents per roundabout are far less common than accidents per traditional crossroad.

Sorry, didn't write the whole thing. Yes, it's much less accidents and those that happen are at much lower speeds and leads to less bad accidents.

Re: Safety benefits of roundabouts

#310

Post by dagw »

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…

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.
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