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Safety benefits of roundabouts

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Re: Safety benefits of roundabouts

#271

Post by autoexec »

rembicilious wrote: post #207
dublinben wrote: post #193

Earlier quoted context omitted.

The car from the inner lane swiping into the car in the outer lane is the exact issue I'm talking about. The problem is when drivers enter in the left/inner lane, fully intending to take the first exit. If they proceed to exit directly from the inner lane, without first changing lanes, signalling, or yielding to outer traffic, they would intersect with a car in the outer lane innocently heading to the second exit. In…

It’s still safer than a normal intersection. Roundabouts prevent HIGH SPEED t-bone and head-on collisions. The difference in safety is easily worth the “cognitive load” of a 2-lane roundabout. I think drivers will get used to them and in practice there will be few collisions.

> I think drivers will get used to them and in practice there will be few collisions.

I think drivers will avoid them at all costs since even low speed collisions can cause extremely expensive repairs (and even total an older vehicle) meaning they'll never get the practice they need to navigate them safely, yet eventually those drivers will find themselves in a situation where a roundabout can't be avoided and suddenly it's chaos for every car in the intersection.

Even if multi-lane roundabouts were suddenly everywhere we'd probably need generations of new drivers trained to use them in drivers ed classes as teens before you could just trust people to be able to navigate them correctly

Re: Safety benefits of roundabouts

#272

Post by hawski »

axiolite wrote: post #249
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…

> The greatest thing about roundabouts is that they protect against the idiot that goes through an intersection at full speed. Who is protected exactly? https://c.tenor.com/GLRaFTDEqngAAAAd/roundabout-poland.gif https://c.tenor.com/0YMymTe85q8AAAAd/roundabout-car.gif

For the first one here's a video about it: https://youtu.be/aniguxnz9ik?t=9 It jumped around 7m high and 64m far.

Re: Safety benefits of roundabouts

#273

Post by RyanHamilton »

michaelt wrote: post #253
occz wrote: post #230

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. This can surely be remedied by having the crossings being raised, acting as speed bumps for the cars and providing a better crossing experience for the pedestrian (or cyclist). I'm not entirely convinced that the lack of lights would inherently mean that roundabouts are less safe for pedestr…

Here in the UK, any difficult-to-cross junction will have a roundabout, simply because our road designers love roundabouts. And for large/busy roundabouts, cars will be in constant motion meaning there won't be gaps in the traffic flow for pedestrians to cross. If you try to cross [1] on foot at a busy period, it's not a particularly fun experience. Of course, I'm not sure any road layout could make such a junction e…

That link is an out of town shopping/restaruant area with nearby suburbs on the edge of town. In fact the whole town of Borehamwood looks like a London commuter town built for cars. low density semi-detached housing with every house having 2 cars. Very depressing. Trying to make that friendly is like trying to make a race car fuel efficient. Somewhere like Brighton, where places are walkabale is much nicer.

Re: Safety benefits of roundabouts

#274

Post by Reason077 »

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 a good thing if it encourages drivers to be alert and cautious. The safest road/intersection designs aren’t necessarily the ones that encourage you to relax and feel comfortable.

Re: Safety benefits of roundabouts

#275

Post by autoexec »

kazinator wrote: post #172
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.

All roundabouts prevent vehicles from just blowing straight through the intersection in the desired direction without so much as slowing down. They remove the middle part of the intersection where conflicting paths intersect. Two-lane roundabouts are larger; cars go around them faster. There is ambiguity. Some cars short-cut using the middle lane, and veer right out of it to their desired exit. Cars in the outer lane…

> I don't think these situations will typically lead to anything worse than fender benders.

Since even a fender bender can cost many thousands of dollars in repairs that's still pretty terrible. Speed bumps slow drivers down too and don't risk people turning into you because they were trying to exit from the inside lane of a roundabout.

Re: Safety benefits of roundabouts

#276

Post by xen0 »

meheleventyone wrote: post #265
xnorswap wrote: post #262

Earlier quoted context omitted.

Careful with terminology too, because "inside" and "outside" don't mean the same thing to different drivers, particularly in the UK compared to elsewhere. Many people hear "inside lane" on a motorway and think it's the "fast lane" near the central divider but that's actually the "outside lane". ( source: https://dictionary.cambridge.org/dictionary/english/outside-... ). But that terminology has been confused over tim…

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.

Re: Safety benefits of roundabouts

#277

Post by hellotheretoday »

I grew up in a touristy part of New Jersey near the beach and roundabouts were interesting. In the off season they were a fine and normal part of driving that the local population were generally used to. Occasionally you’d have a new driver or out of town person that would be confused but that was somewhat rare.

Then the summer months would come and the circles would be a nightmare, filled with dipshits from the surrounding states that had no idea of how they worked despite the fact that the majority of them were single lane! You would really dread the double lane ones though as they would be filled with people who would have no idea how to proceed. You would often see people go around several times before they’d finally exit when there was a lull in traffic

Re: Safety benefits of roundabouts

#278

Post by sfn42 »

globular-toast wrote: post #251
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 is a problem with all multi-lane layouts and exacerbated by drivers' behaviour. The problem is road users new to the road do not know which lane to be in already and they are pressured to go fast. The instant it looks like they've chosen a lane, a driver from behind who is familiar with the layout closes the gap in the other lane, trapping them. This can be mitigated a bit by the first user having the confidence…

It's not a big problem to be in the wrong lane. You just change lanes like any other road. And like any other road, when you change lanes, it's your responsibility to make sure the lane you're merging into has space for you.

Re: Safety benefits of roundabouts

#279

Post by Reason077 »

meheleventyone wrote: post #256
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…

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.

Re: Safety benefits of roundabouts

#280

Post by SanderNL »

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…

I generally dislike these "turbo roundabouts" the first time I encounter them. Always a second of confusion the first time, which is definitely not something I want to feel while driving.

That said, if I enter one I am already familiar with I'm perfectly fine. I guess it depends on who you are optimizing for.

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