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We're excited about our new roundabout

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Re: We're excited about our new roundabout

#191

Post by prmoustache »

Taniwha wrote: post #146
tmnvix wrote: post #140

Roundabouts get a lot of praise whenever they're mentioned, and from a traffic flow perspective that's understandable - if by traffic you mean motorised traffic. For pedestrians and cyclists they are worse than the alternative (lights - or even a simple intersection) in my opinion. > Making a roundabout for everyone ctrl-f "walk", "cycl", pedes". Nothing.

I agree they're a pain for pedestrians (cars are faster, drivers too busy looking at every other car entering the intersection to look at pedestrians) the Dutch do car and bike roundabout well (embedding the car one in a bike one)

Elevated pedestrians crossing (which means the crossing is a speed bump for drivers_ is the solution because roundabouts are actually safer than regular intersections once drivers are forced to slow down.

I know all those speed bumps are annoying when you are driving but elevated crossings and bike paths are great traffic calming solution as screaming your engine between speed bumps soon gets very old and tiring and even the most aggressive drivers just end up staying between 12 and 20mph (20-35kph) in the sections that involve pedestrians and cyclists.

Re: We're excited about our new roundabout

#192

Post by prmoustache »

ifwinterco wrote: post #185
PetitPrince wrote: post #162

Earlier quoted context omitted.

You can have several lanes so that the outer one favor going to the nearest exit: https://maps.app.goo.gl/v76ajKvXhzfAdGZ29 Or you can also have dedicated lane that only go to the nearest exit: https://maps.app.goo.gl/1G2cJf1pWrBkEE5b8

Neither of these really solve the problem if you're trying to go anywhere other than the first exit. OP is right, this is an issue with roundabouts and you end up needing traffic lights in this case (at least at peak times)

Sometimes tunnels are builds to avoid lights when going straight is the direction favored by the majority but it can force an unwanted loop if you stayed on that lane and you didn't realize in time you had to go right to take the roundabout.

Re: We're excited about our new roundabout

#193

Post by larsrc »

I like to hear from the actual traffic planners. Enough laymen rant about why roads are made the way they are, but there are usually considerations they don't know. I'm very curious what kinds of systems get used for planning and what data they have.

Re: We're excited about our new roundabout

#194

Post by watwut »

bane wrote: post #108

This is oddly timely. I'm travelling in Europe at the moment and have been covering a lot of area with a lot of roundabouts where they would be signaled or signed intersections in the US. They definitely make traffic flow smoothly and I've noticed a few areas where they are used to eliminate dangerous left turns at places like parking lots, you leave turning right, hit the next roundabout to "uturn" then head back th…

> They definitely make traffic flow smoothly

They make slow or medium traffic flow smoothly. If the traffic is heavy, roundabouts make everything worst.

Re: We're excited about our new roundabout

#195

Post by FooBarBizBazz »

Roundabouts are hostile to pedestrians. At a 4-way stop, cars actually stop, and they are forced to pay attention. A roundabout is just a vortex of confused drivers who are paying as much attention to what's behind and to the side as they are to what's in front of them. Much better would be to expand the roundabout and straighten its sides until it's a square block with one-way streets -- and so, no longer a roundabout.

The centers of roundabouts are typically overgrown wastes of scraggly grass mixed with litter. Each a tiny sacrifice zone. They remain that way because nobody goes there on foot. We just see the mess from our cars.

A roundabout takes what could have been a village green and turns it into something just barely less terrible than a highway cloverleaf.

...

So I actually read the article and am not really proven wrong. They do this insipid

> Making a roundabout for everyone

thing, like laying pavement is the Civil Rights Movement, but "everyone" seems to only mean "vehicles", a word I see several times, together with "drive", but never "walk". I see no crosswalks, no pedestrian flashers, and no bike lanes. And the center island has been designed so larger vehicles can drive over it; I understand their reasons, but that also means it provides less protection to anyone seeking refuge there as they try to get across.

Sometimes traffic isn't a problem to be solved. It's the universe telling you that there are already too many cars.

Re: We're excited about our new roundabout

#196

Post by ndsipa_pomu »

shiroiushi wrote: post #161
lmm wrote: post #100

Earlier quoted context omitted.

They absolutely are. Even if they don't prevent all collisions, they turn T-bones into glancing hits and so save a lot of lives. The worst roundabout beats the best 4-way stop any day of the week. Sometimes there really are easy answers.

>Even if they don't prevent all collisions, they turn T-bones into glancing hits No, they don't, at least not in America. When you let American traffic engineers design a roundabout, you get this: https://www.google.com/maps/@38.8643875,-77.2755474,583m/

That looks like a Hamburger Junction (or roundabout interchange https://www.roads.org.uk/interchanges/roundabout-interchange).

I think they're a bad design as they encourage drivers to go fast with the sweeping corners etc. Ideally, a roundabout should be designed to slow traffic joining it to reduce collisions and their severity. Trying to keep vehicles moving quickly at junctions is just asking for trouble.

Re: We're excited about our new roundabout

#198

Post by USiBqidmOOkAqRb »

shiroiushi wrote: post #161
lmm wrote: post #100

Earlier quoted context omitted.

They absolutely are. Even if they don't prevent all collisions, they turn T-bones into glancing hits and so save a lot of lives. The worst roundabout beats the best 4-way stop any day of the week. Sometimes there really are easy answers.

>Even if they don't prevent all collisions, they turn T-bones into glancing hits No, they don't, at least not in America. When you let American traffic engineers design a roundabout, you get this: https://www.google.com/maps/@38.8643875,-77.2755474,583m/

It's disheartening to see that much parking place around that spot.

Re: We're excited about our new roundabout

#199

Post by [deleted] »

tmnvix wrote: post #140

Roundabouts get a lot of praise whenever they're mentioned, and from a traffic flow perspective that's understandable - if by traffic you mean motorised traffic. For pedestrians and cyclists they are worse than the alternative (lights - or even a simple intersection) in my opinion. > Making a roundabout for everyone ctrl-f "walk", "cycl", pedes". Nothing.

[deleted]

Re: We're excited about our new roundabout

#200

Post by dmurray »

thepaulmcbride wrote: post #35

I live in the US now, but originally from Ireland. My least favourite part of US road infrastructure is the 4 way stop. They are just not good compared to a roundabout. Half the time the only way you can tell it’s an all way stop is by looking for the back of the stop signs on the perpendicular road. With a roundabout, you only have to look in one direction, and if it’s clear, you don’t even have to stop.

There's one four-way stop I pass regularly in Ireland [0].

I suspect there isn't enough room for a roundabout, and we also don't tend to construct roundabouts on hills (I'm not sure why they're any worse than other junctions there). There's a steep gradient going uphill from South to North.

Normally it would be a two way stop, and I sometimes wonder why that wasn't chosen here. Likely because visibility is bad (trees, walls, curves - it's worse than it looks in the satellite image) and cars coming from the east and west can't completely tell that it's safe to enter the junction.

[0] https://maps.app.goo.gl/i5pezayHLJEDPEPLA

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