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Safety benefits of roundabouts

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Re: Safety benefits of roundabouts

#341

Post by denton-scratch »

CalRobert wrote: post #314
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…

Choice stress is what makes it safe, though. The driver _should_ be a bit stressed. And removing the possibility to change your mind in the roundabout reserves more mental capacity for looking for pedestrians (like me! Hi from Hilversum, which is pretty crappy by Dutch standards but a dream compared to anywhere else I've lived)

There was a fad a couple of decades ago for "mini-roundabouts". They woud install these at junctions with a record of accidents. They were dirt-cheap, because they consisted of simply a couple of roundabout signs, and a circular bump about 6" high and a yard or so across, with smooth sides (i.e. no curb, you could easily drive straight over the bump).

The rationale for these things was that they induce uncertainty in the driver, prompting him to slow down, pay more attention, and look more carefully. There are other schemes that were intended to induce uncertainty. The problem with all these schemes is that they depend on unfamiliarity to work; once a particular mini-roundabout is familiar, it no longer induces uncertainty.

On the ring-road around my hometown, there is a series of "hamburger roundabouts". These are large, multilane roundabouts, with traffic-lights as well, and with a lane-pair that runs straight across the central circle, for through traffic. These configurations have never become at all familiar to me; they always induce uncertainty, and I hate them.

Re: Safety benefits of roundabouts

#342

Post by sputr »

rapnie wrote: post #260
gnosek wrote: post #257

Earlier quoted context omitted.

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.

Seems like that from your description the turbo roundabout is only a problem for people who do not know it or know where there are going.

We have both types here. And now that I think about it, the turbo trades a bit more stress on first usage or a lot less every time after that. While the standard 2 or 3 lane is always similarly stresfull.

We do have a partially soft design of turbo roundabouts with phisical deviders and designated places where you can change a lane.

Re: Safety benefits of roundabouts

#343

Post by viraptor »

CalRobert wrote: post #314
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…

Choice stress is what makes it safe, though. The driver _should_ be a bit stressed. And removing the possibility to change your mind in the roundabout reserves more mental capacity for looking for pedestrians (like me! Hi from Hilversum, which is pretty crappy by Dutch standards but a dream compared to anywhere else I've lived)

> And removing the possibility to change your mind in the roundabout reserves more mental capacity for looking for pedestrians

I don't buy it. Ending up forced to take an unexpected exit in a city triggers a lot of things for me and none of those are pedestrians:

- which lane should I be in for the quickest way back?

- what are the rules on the road I'm turning into? (this may be extremely not obvious if you didn't remember the sign for the road you weren't supposed to be on)

- does this road have restrictions that mean I actually can't be on it?

- is this going to send me on a toll road? (the joys of ending up on a single lane bridge which requires coins to cross and there's 5 cars already queued up behind you)

It's less of an issue for country roads, but being in the wrong lane in a place like this: https://maps.app.goo.gl/H8p1n8dcJ9D8epDG6 may mean you're doing a 30min detour to the same intersection and you'd better get it right this time!

Re: Safety benefits of roundabouts

#344

Post by Moru »

Symbiote wrote: post #120
pandaman wrote: post #103

Earlier quoted context omitted.

The protection is just by hiding half of the traffic beyond an obstacle, you can still get t-boned on the roundabout, but only by the cars from your right and not from both directions like on an intersection. I guess it's a plus but with the added danger of a head-on collision from people traversing the roundabout in the wrong way I won't say if it's net-positive safety-wise with any degree of confidence.

I have never seen anyone go the wrong way around a roundabout, and I've never heard anyone tell me they've seen it. It's so rare you can ignore it.

I have seen two cars but we have an extraordinarily amount of roundabouts so plenty of samples. Those two was in a roundabout that is a bit straighter than normal roundabout so it is possible to turn the wrong way without too much hassle but you still have to be pretty unused to roundabouts to manage it.

Re: Safety benefits of roundabouts

#345

Post by SturgeonsLaw »

ehnto wrote: post #233
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.

Australia does well, but not everywhere. We also had our few decades of automania, that saw our tram lines ripped up in the burbs, and sprawl reach outward with highways. I had to battle this old auto-topian design this week in order to take my car to a mechanic, ironically. There is a train station about 500 meters behind the workshop, as the crow flies. I thought I would just drop my car off, walk to the train, hea…

I was in Perth recently and walked to a cafe to get some lunch, and in this particular area, there were no footpaths at all. It was an industrial/commercial area with factories everywhere, and everything was either carpark, with cars in it, grass strips, with cars parked on it, or road, with cars driving on it.

Re: Safety benefits of roundabouts

#346

Post by zik »

Dah00n wrote: post #267
zik wrote: post #224

Earlier quoted context omitted.

It's a documented effect of roundabouts that they tend to result in more pedestrian fatalities than other forms of intersection. But it does depend on the design - it's possible to improve pedestrian safety at the cost of traffic throughput. Guess which choice my country made...

Do you have a link to those numbers? Here in Denmark it is the opposite.

Your designs are probably far better than ours in Australia. In Australia pedestrians have no right of way at roundabouts and pedestrian crossings aren't normally provided. Basically you cross at your own risk, and it's pretty risky at higher speed, multi-lane roundabouts.

This can all be easily be fixed by designing roundabouts with pedestrians in mind. Unfortunately that doesn't seem to be the case in Australia.

Re: Safety benefits of roundabouts

#347

Post by Moru »

davidw wrote: post #198

When my wife and I moved to Bend, Oregon from Italy, I was really shocked to see how much the city had embraced roundabouts. I hadn't expected to see any in the US, let alone more than 20 of them throughout the city. Not quite sure what the exact history was, but they realized a few years back that they cost less and work pretty well.

Spoke to a taxi driver here in town, he was pretty tired of them. Our small town has 70+, he had counted them... But they do make trafic smoother if placed right. Here however they use them instead of the normal highway crossings with elevated or lowered access roads. As you say, they cost much less and lowers the accidents a lot. But they are not fuel efficient on 80 km/h roads where you have to stop every 500 m because of another roundabout.

Re: Safety benefits of roundabouts

#348

Post by kqr »

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…

Ohh, these turbo roundabouts also prevent doing multiple laps while figuring out where you need to go. I can see how that'd be stressful when you're in new locations!

Re: Safety benefits of roundabouts

#349

Post by meheleventyone »

Reason077 wrote: post #279
meheleventyone wrote: post #256

Earlier quoted context omitted.

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…

> “In the UK you’re expected to filter to the outside leave.” In practice, large multi-lane roundabouts in the UK usually have lane markings as you enter, with specific lanes for each exit. In general, so long as you were in the correct lane as you entered the roundabout, the lane markings should guide you to the correct exit and you shouldn’t have to do any filtering.

Yeah for sure, otherwise it'd be quite scary! Although there are plenty, particularly where there might be more exits where its pretty easy to mispredict where your lane will end up.

Re: Safety benefits of roundabouts

#350

Post by CalRobert »

saiya-jin wrote: post #319
CalRobert wrote: post #314

Earlier quoted context omitted.

Choice stress is what makes it safe, though. The driver _should_ be a bit stressed. And removing the possibility to change your mind in the roundabout reserves more mental capacity for looking for pedestrians (like me! Hi from Hilversum, which is pretty crappy by Dutch standards but a dream compared to anywhere else I've lived)

A person more stressed has less mental capacity for everything else including pedestrians, why the heck do I have to explain this to adults? Stress leads to mistakes, every single time, in any activity. Whole sports and strategies are based solely on making competitor more stressed to induce mistakes and lose.

You might find https://news.ycombinator.com/newsguidelines.html an interesting read.

And there's ample research showing that drivers respond to low-stress designs by going faster and not paying as much attention to things on the periphery. https://grist.org/cities/heres-why-narrower-streets-are-safe... or the illustration at https://i.pinimg.com/originals/e2/e0/dd/e2e0dd89a67fe1df1e6d... are useful.

Would you be so kind as to explain to me your thinking to the contrary, ideally with sources?

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