Two-lane roundabouts still confuse me a bit. Even the video tutorial in that article has what looks like a problem to me. At 1:06, the pink car in the right lane skips the first exit. How does the orange car in the left lane know it's safe to take the second exit? That's a collision risk right there if the pink car wants to continue counter-clockwise.
Safety benefits of roundabouts
81–90 of 409 posts
Re: Safety benefits of roundabouts
#82The 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…
Not necessarily. Some roundabouts have the center circle partially paved so that oversize loads can drive right through if needed. There are curbs, speed bumps and road pillars that make it obvious for normal traffic not to take the shortcut. It also doesn't fully protect vehicles already inside the roundabout. My father got rear-ended once while inside a roundabout by a possibly distracted driver and the car was a n…
> Some roundabouts have the center circle partially paved
This is the "truck apron". Virtually every roundabout in our town has one, and it's up a little curb to get onto it. A little too much for cars to sensible abuse, but a dirt motorbike gets over them easily. :) Also when it snows in people can't tell where the apron starts, so traffic tends to cut over it.
Re: Safety benefits of roundabouts
#83I grew up in a town in Australia nicknamed "The City of Roundabouts". Essentially all intersections in the entire town are roundabouts, including two lane ones, etc. It's quite common to drive the entire length of town (~20 blocks) in reasonably heavy traffic without ever stopping. On a good day you do it in 2nd gear, the whole way. At night you can do it in 3rd gear, because it's exceptionally easy to see headlights…
In my two decades of driving I’ve seen one 4-way stop in Australia. The intersection of Dickson Avenue and Clarendon Street, Artarmon NSW. Haven’t seen one anywhere else.
As someone from the US, I find this quite overly entertaining. "Find the one 4-way stop on the continent!"
They're so common in the US that 3-way or 2-way stops are often marked as such so that you don't make any assumptions about cross traffic stopping.
And please don't misunderstand me--I'm definitely envious.
Re: Safety benefits of roundabouts
#84Two-lane roundabouts still confuse me a bit. Even the video tutorial in that article has what looks like a problem to me. At 1:06, the pink car in the right lane skips the first exit. How does the orange car in the left lane know it's safe to take the second exit? That's a collision risk right there if the pink car wants to continue counter-clockwise.
The pink car is in the wrong lane if it wants to stay on the roundabout for a later exit. The pink car can take either the first or second exits here. The orange can take the second, third, etc.
Re: Safety benefits of roundabouts
#85Two-lane roundabouts still confuse me a bit. Even the video tutorial in that article has what looks like a problem to me. At 1:06, the pink car in the right lane skips the first exit. How does the orange car in the left lane know it's safe to take the second exit? That's a collision risk right there if the pink car wants to continue counter-clockwise.
The pink car is in the wrong lane if it wants to stay on the roundabout for a later exit. The pink car can take either the first or second exits here. The orange can take the second, third, etc.
The lines on the road are incorrect in the video; the pink car should not have been able to go straight.
Based on the lines used in the 2-lane roundabout in the video in question, all right lane entrances should be forced to take the first exit.
Properly signed roundabouts make this clear. Here's an example: https://www.google.com/maps/@44.1104851,-121.2794584,97m/dat...
Re: Safety benefits of roundabouts
#86In 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 roundab…
One of the downsides, of course, is the space. Car infrastructure is already an horrendous waste of space as it is.
Re: Safety benefits of roundabouts
#87The 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…
As long as that center circle is high enough. I had a woman in a Toyota (Camry?) fly over one at about 45+mph and slam into me as I looped around it. Totaled her car, broke parts off my Explorer (repairable). Her son then tried to attack me with my bumper. She kept insisting I turned in front of her (technically true, I was in a roundabout). She was arrested for drunk driving, and, later on, fined for all the flowers…
Was there any kind of barrier within the circle besides flowers?
Re: Safety benefits of roundabouts
#88Interesting that there are no listed downsides. I saw a more balanced article a while back and recall that it listed cost (especially of the additional real estate, since roundabouts are larger) as being one downside. And in built-up cities, it's basically impossible to convert traditional intersections to roundabouts, because there's simply no room. It is nice to not have to pay for replacement signals, or have to d…
Roundabouts are great (and common where I live), but a downside is they can be difficult for pedestrians to cross. You need crossings that are set back from the exits, but this also makes it a longer path for the pedestrian.
Yeah but who cares about pedestrians, or bikes, or anything other than 2-ton metal boxes carrying 1 person at a time. Give me 3 lane roundabouts onto 6-lane stroads please baby!
Re: Safety benefits of roundabouts
#89Earlier quoted context omitted.
As long as that center circle is high enough. I had a woman in a Toyota (Camry?) fly over one at about 45+mph and slam into me as I looped around it. Totaled her car, broke parts off my Explorer (repairable). Her son then tried to attack me with my bumper. She kept insisting I turned in front of her (technically true, I was in a roundabout). She was arrested for drunk driving, and, later on, fined for all the flowers…
Was there any kind of barrier within the circle besides flowers?
The curb she flew over and some brick paving stones used as the perimeter of the little garden, which was enough to stop non-drunk drivers, but no wall or anything.
Re: Safety benefits of roundabouts
#90I'm not a traffic engineer, but I think roundabouts take more space than an equivalent signal or stop sign intersection. The article says that many places are starting to default to roundabouts, but many intersections are likely going to be difficult to upgrade.
if roundabouts are already common and drivers behave, a mini roundabout can work
but if they aren't common, so you need to construct it in a way that requires compliance, more space is required