My best friend is a highly experienced civil engineer, specialized in designing intersections. His take on roundabouts:
- They are adored by urban planners because they look nice and you can put a statue or fountain in the middle
- They reduce T-bone collisions
However:
- Small fender benders and sideswipes are much more frequent
- They use way more area
- They work where each direction has an approximately equal amount of traffic. However, usually, one direction (north/south, say) has a larger share of the traffic. In those cases, the bulk of traffic all needs to slow down, downshift, turn a bit in one direction and then turn a bit in the other direction for the minority of traffic that's bleeding on or off the main artery. In those cases, a traffic light is better because the timing can be adjusted to the proportion of traffic from each direction (and more flexible since it can be adjusted over time).
- Finally, they're also (mostly) worse for cyclists and pedestrians.
Essentially, they have use cases, especially in small towns, and they're pretty, but they're usually not the right engineering solution.
> the bulk of traffic all needs to slow down, downshift, turn a bit in one direction and then turn a bit in the other direction for the minority of traffic that's bleeding on or off the main artery.
Slowing/calming traffic like this is a good thing. Make it impossible to speed. Enforce the existing 35mph speed limit via concrete rather than allowing cars to rip through a yellow light at 70mph. You're also ignoring this aspect when you call roundabouts "(mostly) worse for cyclists and pedestrians".
A place where traffic slows down, without actually stopping, and becomes congested with no time/space gaps between vehicles, is worse for pedestrians.
However there are often pedestrian crossings across the roads or the volume is low enough pedestrians can easily cross. A local roundabout got busy enough we had crossing added less than 10 years ago and the biggest road there was a minor B road.
I am a pedestrian due to sight issues and have found very few places where it is difficult to cross when needed.
The "when needed" suggests that there are plenty of difficulty to cross intersections, you're just able to avoid them. Is that accurate?
This is true if you can alter the properties of the physically existent universe, else it is not true, and, indeed, drivers do not even slow down largely because they feel frustrated when traveling along a road with a 45 MPH speed limit at an average speed of 20 MPH.
> becomes congested with no time/space gaps between vehicles, is worse for pedestrians
Why? This feels like it's assuming pedestrians share the street with vehicles, but besides the US and some other places, don't most "modern" countries have separate pavements/streets for pedestrians? Besides in the country-side, vehicles and pedestrians don't generally share the road in populated areas here in Spain. For crossing roads outside cities, building a pedestrian tunnel below or a bridge above seems to preferred here, except in the cases where it isn't possible, and in cities obviously.
Right, you're talking about "traffic participant", are you including pedestrians or not? Because as I said, in many places, "vehicles" and "pedestrians" are well-separated and don't impact/affect each other, so not sure what cluster-fuck could be created there. Seems less of a cluster-fuck than relying on cross-walks and stop-lights?
There used to be an epidemic of cars striking and killing pedestrians. The advertising industry (hired by the auto industry) came up with the new imaginary crime called "jaywalking". This diverted attention from the killers and onto the victims. Just one more version of the victim blaming that derives from the Just World Hypothesis.
> A 1993 study in the Netherlands examined collision experience at 181 intersections converted to roundabouts. Pedestrian collisions (all injury severities) dropped 73% and pedestrian casualties dropped 89%.
> Evaluations in Sweden concluded that single-lane roundabouts are very safe for pedestrians, at about a 78% reduction in injuries, and that multi-lane roundabouts are about as safe as other intersections.
> A 2002 study of collision experience at the roundabouts in Park City, Vail, West Vail and Avon, Colorado, showed 2 pedestrian crashes prior to the roundabouts operating with
over 164 million vehicle movements, compared to 1 pedestrian crash with roundabouts experiencing over 282 million vehicle movements.
> With the installation of a roundabout, this study finds that the before-after analysis results in a 40% decrease in all severity injury crashes for all roadway users, a 70% decrease in fatal and serious injury crashes for bikes and pedestrians, and a 15% decrease in total pedestrian bike and pedestrian crashes.
OK, so "worse for pedestrians" boils down to a statistic about body hits. If you are not struck, you are not having a worse pedestrian experience. My bad!
It can be a good thing. But I've seen many roundabouts in the US (specifically in the state of Wisconsin) where someone decided to put a roundabout on a major rural highway that was crossed by a side road. In that case there is no sense in having the 60mph traffic stop just for an occasional car crossing or turning. The side road should have a stop sign while the main road flows unimpeded.
The new roundabout completely prevents fatality t-bone crashes into people turning left from those stop signs, which has likely happened multiple times at that very intersection thus prompting the road to be redesigned.
propter_hoc · · focus · HN ↗
- They are adored by urban planners because they look nice and you can put a statue or fountain in the middle
- They reduce T-bone collisions
However:
- Small fender benders and sideswipes are much more frequent
- They use way more area
- They work where each direction has an approximately equal amount of traffic. However, usually, one direction (north/south, say) has a larger share of the traffic. In those cases, the bulk of traffic all needs to slow down, downshift, turn a bit in one direction and then turn a bit in the other direction for the minority of traffic that's bleeding on or off the main artery. In those cases, a traffic light is better because the timing can be adjusted to the proportion of traffic from each direction (and more flexible since it can be adjusted over time).
- Finally, they're also (mostly) worse for cyclists and pedestrians.
Essentially, they have use cases, especially in small towns, and they're pretty, but they're usually not the right engineering solution.
pkamb · · focus · HN ↗
Slowing/calming traffic like this is a good thing. Make it impossible to speed. Enforce the existing 35mph speed limit via concrete rather than allowing cars to rip through a yellow light at 70mph. You're also ignoring this aspect when you call roundabouts "(mostly) worse for cyclists and pedestrians".
kazinator · · focus · HN ↗
tokai · · focus · HN ↗
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kazinator · · focus · HN ↗
tremon · · focus · HN ↗
agwa · · focus · HN ↗
paulnpace · · focus · HN ↗
bulder · · focus · HN ↗
pasc1878 · · focus · HN ↗
However there are often pedestrian crossings across the roads or the volume is low enough pedestrians can easily cross. A local roundabout got busy enough we had crossing added less than 10 years ago and the biggest road there was a minor B road.
I am a pedestrian due to sight issues and have found very few places where it is difficult to cross when needed.
sagarm · · focus · HN ↗
pasc1878 · · focus · HN ↗
paulnpace · · focus · HN ↗
embedding-shape · · focus · HN ↗
Why? This feels like it's assuming pedestrians share the street with vehicles, but besides the US and some other places, don't most "modern" countries have separate pavements/streets for pedestrians? Besides in the country-side, vehicles and pedestrians don't generally share the road in populated areas here in Spain. For crossing roads outside cities, building a pedestrian tunnel below or a bridge above seems to preferred here, except in the cases where it isn't possible, and in cities obviously.
ubercore · · focus · HN ↗
* a small roundabout with really clear pedestrian right of way marked
* a pedestrian path that takes you over or under the road instead of crossing it
It's great!
cucumber3732842 · · focus · HN ↗
embedding-shape · · focus · HN ↗
cucumber3732842 · · focus · HN ↗
embedding-shape · · focus · HN ↗
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dang · · focus · HN ↗
<a href="https://news.ycombinator.com/newsguidelines.html">https://news.ycombinator.com/newsguidelines.html
dang · · focus · HN ↗
<a href="https://news.ycombinator.com/newsguidelines.html">https://news.ycombinator.com/newsguidelines.html
Tangurena2 · · focus · HN ↗
<a href="https://en.wikipedia.org/wiki/Just-world_fallacy" rel="nofollow">https://en.wikipedia.org/wiki/Just-world_fallacy
throw0101c · · focus · HN ↗
Some data seems to conflict with this:
> A 1993 study in the Netherlands examined collision experience at 181 intersections converted to roundabouts. Pedestrian collisions (all injury severities) dropped 73% and pedestrian casualties dropped 89%.
> Evaluations in Sweden concluded that single-lane roundabouts are very safe for pedestrians, at about a 78% reduction in injuries, and that multi-lane roundabouts are about as safe as other intersections.
> A 2002 study of collision experience at the roundabouts in Park City, Vail, West Vail and Avon, Colorado, showed 2 pedestrian crashes prior to the roundabouts operating with over 164 million vehicle movements, compared to 1 pedestrian crash with roundabouts experiencing over 282 million vehicle movements.
* <a href="https://www.tac-atc.ca/wp-content/uploads/weber.pdf" rel="nofollow">https://www.tac-atc.ca/wp-content/uploads/weber.pdf
> With the installation of a roundabout, this study finds that the before-after analysis results in a 40% decrease in all severity injury crashes for all roadway users, a 70% decrease in fatal and serious injury crashes for bikes and pedestrians, and a 15% decrease in total pedestrian bike and pedestrian crashes.
* <a href="https://mdl.mndot.gov/items/202336" rel="nofollow">https://mdl.mndot.gov/items/202336
kazinator · · focus · HN ↗
bigstrat2003 · · focus · HN ↗
pkamb · · focus · HN ↗