8 ms·

I think roundabouts with pedestrian crossing lights solves the problem. Roundabouts alone also reduce accidents or make them less severe.

giraffe_lady 4y ago
They reduce car crashes with other cars. I don't know off the top of my head if they reduce car-pedestrian crashes but I suspect not. I used to live off of a busy roundabout in a place that makes heavy heavy use of roundabouts (almost no four-way stops). It felt dangerous as fuck honestly. The crosswalks are a little "downstream" of the true circle, where cars have already begun to exit. Frequently (saw this a few times myself) a car would stop for a pedestrian and then get rear-ended by another car focused on exiting the roundabout. This was not the US so unfamiliarity with roundabouts can't be blamed. They were the norm there.
- throw_me_up 4y ago
  Did they have large, flashing crossing lights for pedestrians to turn on?
  - giraffe_lady 4y ago
    Not the one I lived by, but some of them did, yes!
Misdicorl 4y ago
How small can you make a roundabout? Where I live stop signs are common at very small intersections. Alternating two way stops (n/s at intersection one, e/w at intersection two) seems like maybe an ok way to reduce the problem by half at little to no cost?
- ajb 4y ago
  The UK historically has lots of roundabouts, the design guidelines are here : https://www.google.com/url?q=https://trl.co.uk/uploads/trl/documents/PPR206_secure.PDF&sa=U&ved=2ahUKEwjZ-ua4_5b3AhXAQEEAHR1_AF4QFnoECAoQAg&usg=AOvVaw0ma_Cnbl_N5_1ZJ4h0doaH https://www.google.com/url?q=https://trl.co.uk/uploads/trl/d... Basically they recommend 28m diameter if you are going to have a central island, otherwise it should be a mini-roundabout (capable of being driven over)
  - alistairSH 4y ago
    I’ll add that in my family’s home town (farming town in Perthshire) in Scotland, there are mini roundabouts that are just a spot of white paint in the middle of the intersection. It works fine.
- adhesive_wombat 4y ago
  Pretty small: a mini roundabout isn't really any bigger than just the intersection: https://en.wikipedia.org/wiki/Roundabout#Mini-roundabouts https://en.wikipedia.org/wiki/Roundabout#Mini-roundabouts
  - pm3003 4y ago
    Mini roundabouts are very likely to be confusing horrors, outside of low-speed residential zones, parking lots and the like. See the city of Nantes in France (roundabout’s paradise), navigating the intersections is horrible. In a few parts of town they even have double mini roundabouts. The only reasonable explanation I found is “security by confusion” : if you have no idea how to drive through the intersection, you’re more likely to slow down. Well it doesn’t make the intersection really safer.
- Mountain_Skies 4y ago
  I've seen some in Vancouver that are little more than an oversize planter with a scrub in it stuck in the middle of the intersection. As long as it deflects traffic to the side a bit, a slowdown is achieved and the main purpose fulfilled.
  - fassssst 4y ago
    Yea there are a bunch of those in Seattle neighborhoods, they work well.
    - kn0where 4y ago
      In my experience with the ones in Seattle, people who are turning left use the wrong side of the mini roundabout to save 3 seconds of driving time.
- hedora 4y ago
  There's a configuration for bike safety that's basically a mini roundabout superimposed on a normal intersection. It doesn't significantly increase the size of the intersection, but the geometry works out in a way where bikes can go at near full speed, but it's impossible for a right turning car and straight going bike to get into a collision without seeing each other first (assuming both are looking forward while driving).
  - aix1 4y ago
    Is there a picture/diagram you could link to that would show this configuration in more detail?
jimmygrapes 4y ago
Roundabouts generally require a driver to look in a direction other than their direction of travel, to determine if it is safe to go. They are also designed to reduce the amount of time any given vehicle has to actually stop if there is no reason to. However, to keep the flow, a driver must check if there is incoming traffic. This varies based on left/right side driving countries. Lights for pedestrians might help, but then the benefit of continual traffic flow is reduced. There are more considerations that can make it work, but I often see this point (my first sentence) overlooked.
- uoaei 4y ago
  > Roundabouts generally require a driver to look in a direction other than their direction of travel, to determine if it is safe to go. True for stop signs... and any other traffic control solution in existence, frankly. Yielded merges are the most obvious form of specifically unbroken traffic flow that requires the same. > They are also designed to reduce the amount of time any given vehicle has to actually stop if there is no reason to. So it works like a yield. That's a good thing because it reduces congestion. > This varies based on left/right side driving countries. There are much bigger issues resulting from switching between left- and right-side driving standards which don't have anything to do with roundabouts, so this doesn't say anything about roundabouts so much as the difference in standards. > Lights for pedestrians might help, but then the benefit of continual traffic flow is reduced. Comes with the territory, and is also true of every other traffic control solution in existence. The complete solution to this is to completely separate pedestrian and vehicular traffic, which is also not limited to roundabouts. It sounds like you don't have a problem with roundabouts so much as traffic control per se, if you believe these to be reasons not to implement roundabouts.
  - dataflow 4y ago
    >> Roundabouts generally require a driver to look in a direction other than their direction of travel, to determine if it is safe to go. > True for stop signs... Not really. Stop signs make you stop first, before needing to look around, after which you continue. There's no "direction of travel" when you've stopped; you're not traveling when you've stopped. Meaning you can focus on one thing at a time, unlike with a roundabout.
aaron_m04 4y ago
Every time I see a crosswalk near a roundabout, I think that's a terrible place for a crosswalk (the drivers are distracted by figuring out if they need to stop, and when it's clear to keep going).
- awiesenhofer 4y ago
  They shouldn't be, if a driver is already looking into the roundabout before even reaching the crosswalk they are simply driving too fast. Just as with yield signs you should be able to stop in time when needed.
  - aaron_m04 4y ago
    > They shouldn't be, if a driver is already looking into the roundabout before even reaching the crosswalk they are simply driving too fast. I mean, yes, they are driving too fast. Given that drivers do drive too fast, it's a bad place for a crosswalk.

giraffe_lady 4y ago

They reduce car crashes with other cars. I don't know off the top of my head if they reduce car-pedestrian crashes but I suspect not. I used to live off of a busy roundabout in a place that makes heavy heavy use of roundabouts (almost no four-way stops). It felt dangerous as fuck honestly. The crosswalks are a little "downstream" of the true circle, where cars have already begun to exit. Frequently (saw this a few times myself) a car would stop for a pedestrian and then get rear-ended by another car focused on exiting the roundabout. This was not the US so unfamiliarity with roundabouts can't be blamed. They were the norm there.

throw_me_up 4y ago
Did they have large, flashing crossing lights for pedestrians to turn on?
- giraffe_lady 4y ago
  Not the one I lived by, but some of them did, yes!

Misdicorl 4y ago

How small can you make a roundabout? Where I live stop signs are common at very small intersections. Alternating two way stops (n/s at intersection one, e/w at intersection two) seems like maybe an ok way to reduce the problem by half at little to no cost?

ajb 4y ago
The UK historically has lots of roundabouts, the design guidelines are here : https://www.google.com/url?q=https://trl.co.uk/uploads/trl/documents/PPR206_secure.PDF&sa=U&ved=2ahUKEwjZ-ua4_5b3AhXAQEEAHR1_AF4QFnoECAoQAg&usg=AOvVaw0ma_Cnbl_N5_1ZJ4h0doaH https://www.google.com/url?q=https://trl.co.uk/uploads/trl/d... Basically they recommend 28m diameter if you are going to have a central island, otherwise it should be a mini-roundabout (capable of being driven over)
- alistairSH 4y ago
  I’ll add that in my family’s home town (farming town in Perthshire) in Scotland, there are mini roundabouts that are just a spot of white paint in the middle of the intersection. It works fine.
adhesive_wombat 4y ago
Pretty small: a mini roundabout isn't really any bigger than just the intersection: https://en.wikipedia.org/wiki/Roundabout#Mini-roundabouts https://en.wikipedia.org/wiki/Roundabout#Mini-roundabouts
- pm3003 4y ago
  Mini roundabouts are very likely to be confusing horrors, outside of low-speed residential zones, parking lots and the like. See the city of Nantes in France (roundabout’s paradise), navigating the intersections is horrible. In a few parts of town they even have double mini roundabouts. The only reasonable explanation I found is “security by confusion” : if you have no idea how to drive through the intersection, you’re more likely to slow down. Well it doesn’t make the intersection really safer.
Mountain_Skies 4y ago
I've seen some in Vancouver that are little more than an oversize planter with a scrub in it stuck in the middle of the intersection. As long as it deflects traffic to the side a bit, a slowdown is achieved and the main purpose fulfilled.
- fassssst 4y ago
  Yea there are a bunch of those in Seattle neighborhoods, they work well.
  - kn0where 4y ago
    In my experience with the ones in Seattle, people who are turning left use the wrong side of the mini roundabout to save 3 seconds of driving time.
hedora 4y ago
There's a configuration for bike safety that's basically a mini roundabout superimposed on a normal intersection. It doesn't significantly increase the size of the intersection, but the geometry works out in a way where bikes can go at near full speed, but it's impossible for a right turning car and straight going bike to get into a collision without seeing each other first (assuming both are looking forward while driving).
- aix1 4y ago
  Is there a picture/diagram you could link to that would show this configuration in more detail?

jimmygrapes 4y ago

Roundabouts generally require a driver to look in a direction other than their direction of travel, to determine if it is safe to go. They are also designed to reduce the amount of time any given vehicle has to actually stop if there is no reason to. However, to keep the flow, a driver must check if there is incoming traffic. This varies based on left/right side driving countries. Lights for pedestrians might help, but then the benefit of continual traffic flow is reduced. There are more considerations that can make it work, but I often see this point (my first sentence) overlooked.

uoaei 4y ago
> Roundabouts generally require a driver to look in a direction other than their direction of travel, to determine if it is safe to go. True for stop signs... and any other traffic control solution in existence, frankly. Yielded merges are the most obvious form of specifically unbroken traffic flow that requires the same. > They are also designed to reduce the amount of time any given vehicle has to actually stop if there is no reason to. So it works like a yield. That's a good thing because it reduces congestion. > This varies based on left/right side driving countries. There are much bigger issues resulting from switching between left- and right-side driving standards which don't have anything to do with roundabouts, so this doesn't say anything about roundabouts so much as the difference in standards. > Lights for pedestrians might help, but then the benefit of continual traffic flow is reduced. Comes with the territory, and is also true of every other traffic control solution in existence. The complete solution to this is to completely separate pedestrian and vehicular traffic, which is also not limited to roundabouts. It sounds like you don't have a problem with roundabouts so much as traffic control per se, if you believe these to be reasons not to implement roundabouts.
- dataflow 4y ago
  >> Roundabouts generally require a driver to look in a direction other than their direction of travel, to determine if it is safe to go. > True for stop signs... Not really. Stop signs make you stop first, before needing to look around, after which you continue. There's no "direction of travel" when you've stopped; you're not traveling when you've stopped. Meaning you can focus on one thing at a time, unlike with a roundabout.

aaron_m04 4y ago

Every time I see a crosswalk near a roundabout, I think that's a terrible place for a crosswalk (the drivers are distracted by figuring out if they need to stop, and when it's clear to keep going).

awiesenhofer 4y ago
They shouldn't be, if a driver is already looking into the roundabout before even reaching the crosswalk they are simply driving too fast. Just as with yield signs you should be able to stop in time when needed.
- aaron_m04 4y ago
  > They shouldn't be, if a driver is already looking into the roundabout before even reaching the crosswalk they are simply driving too fast. I mean, yes, they are driving too fast. Given that drivers do drive too fast, it's a bad place for a crosswalk.