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comment by goobster
goobster  ·  2318 days ago  ·  link  ·    ·  parent  ·  post: America is now an outlier on driving deaths

Also: Roundabouts.

Jeebus Crisp those things work REALLY WELL.

Roundabout coming up... slow speed a bit... check to the right... look for a hole in traffic... move around the roundabout to your exit... speed up to highway speeds again.

Stopping at traffic lights and stop signs is really fucking annoying after driving in countries with roundabouts.





kleinbl00  ·  2318 days ago  ·  link  ·  

I really hated the shit out of those things until I started dealing with them regularly.

veen  ·  2318 days ago  ·  link  ·  

Preach! They're not great if you are prone to get car sickness, but they are safer by lowering the speed for everyone and in most low-to-medium-volume intersections they can process more traffic from more directions. What I've heard (as in, anecdotally) is that drivers in the US are not taught what it is and that pretty much nobody knows how to properly yield.

Did you also get to see a turbo-roundabout? Instead of a circle, it consists of two interlocking spirals:

My hometown of 100k already has more than a hundred roundabouts, but added a dozen of those in recent years because they can handle a much larger capacity. It obviously has a larger footprint, since two directions need to pick a lane, but it's pretty darn cool.

goobster  ·  2318 days ago  ·  link  ·  

Making a left in that turbo roundabout seems more finicky than it needs to be.

It seems like this is going to be more trouble for anyone that doesn't know exactly where they are going. It also only works where there are 4 potential exits. Add an exit, and the middle lane becomes a wasteland of lost tourists, wandering aimlessly... ;-)

Well ok, maybe not THAT bad! But I think in the UK the majority of the roundabouts had more than 4 exits.

Heck... maybe that's why roundabouts came up in the first place... to make it easier to join multiple roads, rather than just a crossroads...

kleinbl00  ·  2318 days ago  ·  link  ·  

I suspect, like roundabouts in general, it's maddening and/or frustrating until you use it and then you go

...oh...

And then you feel silly for getting so worked up about something that's actually really fucking effective.

veen  ·  2318 days ago  ·  link  ·  

To put some numbers behind it, the theoretical capacity for a regular roundabout is 20-25k vehicles/day, whereas the above can process up to 40k/day, mostly dependent on where the largest flows come from. (A regular intersection with traffic lights can handle between 20-35k.)

goobster  ·  2318 days ago  ·  link  ·  

Ooooh! Numbers! I love data!

Do you have numbers for similar intersections with traffic lights, or stop signs, to compare against the roundabout numbers?

veen  ·  2318 days ago  ·  link  ·  

All directions can use the heuristic 'if you go left, take the left lane, if you go right, take the right lane.' It looks harder than it actually is! You're right though, it's a solution that does not always fit the problem.

Dual-lane roundabouts usually create more confusion because people might not change lanes in time, like here: