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Genuine question, why are four-way stops a thing at all? Here in Australia, the usual setup for uncontrolled residential intersections (that don't have roundab

Genuine question, why are four-way stops a thing at all? Here in Australia, the usual setup for uncontrolled residential intersections (that don't have roundabouts) is to give one axis (?) right of way, and put stop signs on the cross axis. If neither direction is substantially wider or busier than the other, it's usually just arbitrary. This solves the problem of people being confused about right of way. When you come to a stop sign, you just give way to all traffic coming across the intersection.

tbihl 5y ago
I'm guessing your pictured intersections have lower speed limits and tighter geometry. As speeds increase, the amount of physical space needed to enter or cross traffic drastically increases. Even beyond that, as speeds increase, the estimation problem moves further away from human perception into something that would require the perception of a fast predatory bird, so even more space is needed just to be safe. When I think of conversions from 2 to 4 way stops, I think of an intersection in my town where the road was listed at 25mph but the enormously wide pavement easily supported driving 40-45mph comfortably, especially being at the bottom of a steep hill, and people drove accordingly. Completely separate from that is the issue of neighborhood groups trying to get inappropriate stop signs added to calm traffic. Stop signs are only for managing right of way; traffic calming should be handled by changes to street design. Disclaimer: Obviously any answer to this question will be a generalization that doesn't cover all circumstances
mhb 5y ago
> why are four-way stops a thing at all? Where I am, they are certainly overused - of course, because people agitate for them because safety. But you can read all about the traffic engineering justification for them in the Manual on Uniform Traffic Control Devices: https://mutcd.fhwa.dot.gov/htm/2009/part2/part2b.htm#section2B07 https://mutcd.fhwa.dot.gov/htm/2009/part2/part2b.htm#section...
readflaggedcomm 5y ago
Left turns out of a busy street work better if you have a turn to yourself, instead of waiting for traffic to break. There are some arrangements of stop lights that can make that better or much, much worse for one-lane traffic (I have one of each near me).

tbihl 5y ago

I'm guessing your pictured intersections have lower speed limits and tighter geometry. As speeds increase, the amount of physical space needed to enter or cross traffic drastically increases. Even beyond that, as speeds increase, the estimation problem moves further away from human perception into something that would require the perception of a fast predatory bird, so even more space is needed just to be safe. When I think of conversions from 2 to 4 way stops, I think of an intersection in my town where the road was listed at 25mph but the enormously wide pavement easily supported driving 40-45mph comfortably, especially being at the bottom of a steep hill, and people drove accordingly. Completely separate from that is the issue of neighborhood groups trying to get inappropriate stop signs added to calm traffic. Stop signs are only for managing right of way; traffic calming should be handled by changes to street design. Disclaimer: Obviously any answer to this question will be a generalization that doesn't cover all circumstances

mhb 5y ago

> why are four-way stops a thing at all? Where I am, they are certainly overused - of course, because people agitate for them because safety. But you can read all about the traffic engineering justification for them in the Manual on Uniform Traffic Control Devices: https://mutcd.fhwa.dot.gov/htm/2009/part2/part2b.htm#section2B07 https://mutcd.fhwa.dot.gov/htm/2009/part2/part2b.htm#section...

readflaggedcomm 5y ago

Left turns out of a busy street work better if you have a turn to yourself, instead of waiting for traffic to break. There are some arrangements of stop lights that can make that better or much, much worse for one-lane traffic (I have one of each near me).