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We're excited about our new roundabout

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Re: We're excited about our new roundabout

#251

Post by DrBazza »

ndsipa_pomu wrote: post #206
DrBazza wrote: post #171

Earlier quoted context omitted.

Try driving in England, rural or otherwise, and you'll see our current trend of adding traffic lights to roundabouts. If you think roundabouts slow you down (they don't really), just wait until non-rush hour at one of these "roundabouts" when you're the only car waiting on several sets of red lights, or during rush hour when the lights have failed and it's totally gridlocked where traffic simply cannot pass.

To be fair, most of the gridlocked traffic is caused by drivers not understanding that they shouldn't enter a yellow box junction until their exit is clear and similarly, they shouldn't be nosing out onto a roundabout when their lane is already full - that's what tends to cause the issues.

True. It's in the Highway Code. Then again, so is 'move quickly past the vehicle you are overtaking, once you have started to overtake. Allow plenty of room. Move back to the left as soon as you can but do not cut in'. But you wouldn't know it driving on UK motorways.

Re: We're excited about our new roundabout

#252

Post by btbuildem »

Etheryte wrote: post #208
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.

Strong disagree, a well designed roundabout is both safer and faster for both pedestrians and cyclists. See this roundabout [0] from Delft, Netherlands for a good example. Pedestrians have right of way over everyone, then cyclists, and lastly there's a set of traffic lights to give trams and buses right of way when they come by. Cars come last and traffic flows smoothly and safely. [0] https://www.google.com/maps/@51…

I like the order of priority here. It's as if the designers ranked travellers by the magnitude of their kinetic energy, and forced the highest-energy travellers to exercise most caution. How sensical!

Re: We're excited about our new roundabout

#253

Post by bfirsh »

davidgay wrote: post #121
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.

You can actually screw them up: by our house (in California) they replaced a 4-way stop with a roundabout with no signaling on 2 of the ways, and a stop on the other 2. An absolute disaster, as the 2 ways without the stop assumed they had the right of way over people already in the roundabout. After the neighbourhood complained, it's now a roundabout with 4 stops (not ideal, but not dangerous either).

I can confirm these are dangerous. There are several of these in Berkeley and I got knocked off my bicycle on one of them for exactly the reason you describe.

I am from the UK and it makes me wonder why road design in the US is so bad. Just one minute of thinking about this as a lay person would reveal the problem with the design.

Is there some structural reason in the US that would cause it? Perhaps some lack of standards or approval process? Perhaps iteration speed is slower so they don’t get better? Some other incentives going on?

Re: We're excited about our new roundabout

#254

Post by Clent »

bnralt wrote: post #158
Arn_Thor wrote: post #129

Earlier quoted context omitted.

I'd really like to know where this was or see some pictures of it. It's almost inconcievable that something designed like a roundabout would be more dangerous. It might indeed cause more accidents due to the kind of confusion you describe, but at the very least the angles and grading should lower speeds dramatically and result in fewer deadly accidents.

It's set up like this - busy avenue with lanes (left to right) 1, 2, and 3 enter into roundabout with circles (inner to outer) A, B, and C. The problem is that half way around the circle, where the avenue continues, A, B, and C then have lines indicating that you can either continue on the circle or move in a perpendicular direction to the circle and exit back such like this A -> 1, B -> 2, and C -> 3. And that's wha…

I live in an area with many A, B, C as you call them. Assuming we're going backwards, where A is right most lane, with these three lane roundabouts it's always A can only turn right, C an only turn left, B is for going straight, but can also turn right or left.

There are variations on this, sometimes, B can only go straight so that C can also go straight. C can also be used for a fully controlled U-turn. In fact, C is has the markings such that one can just go around and around and around forever in if one chose to do so.

All of the roundabouts here have overhead signage leading up to them that indicates which lanes are for each direction of travel. There are also lines on the roads themselves have solid and dashed lines. Never cross solid lines, optionally cross dashes. We get snow so lines aren't always visible.

I've been through many different roundabouts countless times and there is occasionally someone that doesn't get it right but the traffic is moving slowly enough that it unusually only leads to honking.

One strategy is to watch the faces of other drivers, people will be looking in the direction they will be turning.

Re: We're excited about our new roundabout

#255

Post by mannykannot »

zamadatix wrote: post #247

Given the amount of space if I were driving through it I'd wish they had just made it a little larger so it could be a normal "full circle" roundabout. Sometimes the biggest problems with roundabouts is the number of variations. "You can use this lane to go that way here but a mile up if you want to go that way you want to make sure you're in the other lane". Not to mention it seems somewhat easy to speed through wit…

Yes, this leaves me with an uneasy feeling:

"Drivers going northbound on SR 203 traffic may need to yield twice – once when entering the roundabout and again if traffic is passing between the two islands. If you think about it, that’s just following the same rules a second time." [my emphasis.]

Firstly, of course, if you are new to it and have not heard about it in advance, you won't have much time to think about it. Secondly, if your mental model of a roundabout is "yield to enter, then you have right of way", this will seem counter-intuitive. I hope they put up a yield sign and corresponding road markings at that point, but the latter are not there in the accompanying aerial photo.

I am also curious as to how navigation systems will tell drivers how to negotiate this roundabout. They have trouble with a somewhat similar roundabout in Kingston NY, at the intersection of Albany ave., Broadway and Colonel Chandler drive.

Update: The accompanying video shows there will be yield lines at the point I am concerned about, but it is also ambiguous about how the rules of the road apply there: "The circulating roadway goes around and between both central islands... Those drivers already in the circulating roadway have the right-of-way."

https://www.youtube.com/watch?v=07_m7HHiZRw

Re: We're excited about our new roundabout

#256

Post by artursapek »

btbuildem wrote: post #249
necrobrit wrote: post #149

Earlier quoted context omitted.

The preference for 4 way stops in a country that otherwise prioritises traffic flow so much is really jarring. Traffic lights too to some extent. About 5 years ago my wife an I were doing a California road trip. At one point on a relatively rural road -- I think it might have been Dry Creek road heading into Napa but cannae mind exactly -- we got stuck in traffic for around 45 minutes. We thought there must have been…

90% of stop signs in the US/Canada should actually be yield signs. Stop signs are reserved for "dangerous" intersections, ie spots where a driver can't safely see or make a decision without first stopping. Throwing a red octagon at every single intersection of two roads is lazy and absurd. It encourages people to break the rules (just run the stop sign) and cause accidents (zone out, stop and go without actually look…

Funny, I live in the US and I treat about 90% of stop signs as yield signs. My ex-wife would complain about it to me all the time as if I’m doing something wrong, but I never stopped lol

Re: We're excited about our new roundabout

#257

Post by ndsipa_pomu »

DrBazza wrote: post #251
ndsipa_pomu wrote: post #206

Earlier quoted context omitted.

To be fair, most of the gridlocked traffic is caused by drivers not understanding that they shouldn't enter a yellow box junction until their exit is clear and similarly, they shouldn't be nosing out onto a roundabout when their lane is already full - that's what tends to cause the issues.

True. It's in the Highway Code. Then again, so is 'move quickly past the vehicle you are overtaking, once you have started to overtake. Allow plenty of room. Move back to the left as soon as you can but do not cut in'. But you wouldn't know it driving on UK motorways.

There's a special ring of hell reserved for drivers that stay in the middle lane.

Re: We're excited about our new roundabout

#258

Post by btbuildem »

Karellen wrote: post #189
jayyhu wrote: post #49

Earlier quoted context omitted.

They made a video that explains how to navigate the roundabout, and shows what it will actually look like (with yield markings)[1] [1]: https://youtu.be/07_m7HHiZRw

What the hell is that "dump truck with trailer" on a really long connector at 3:50? Is that a thing in some parts? How does that navigate almost any kind of roadway safely?

They're called "pup" trailers [1] (example photo [2]), and the very long hitch exists for a few reasons: per-axle weight limit, respecting max weight capacity of smaller bridges, and ease of unloading [3] among them.

1: https://titanww.com/what-is-a-pup-trailer/

2: https://imgur.com/raDJVVL

3: https://www.youtube.com/watch?v=mU5L_2TMjKc (sorry, terrible handheld video)

Re: We're excited about our new roundabout

#259

Post by [deleted] »

zlsa wrote: post #99

I live near this roundabout and drive through it almost daily. > Drivers going northbound on SR 203 traffic may need to yield twice – once when entering the roundabout and again if traffic is passing between the two islands. If you think about it, that’s just following the same rules a second time. The one key difference from the average (American) roundabout is the second yield. After you've waited your turn and ent…

[deleted]

Re: We're excited about our new roundabout

#260

Post by rob74 »

consp wrote: post #228
rob74 wrote: post #132

Earlier quoted context omitted.

I'm living in Germany, where roundabouts are very popular with planners recently. I would say they definitely have their place, but they are also overused. The (smallish) city where I live has a bypass road where for some reason it was decided to use roundabouts (I suspect the same reason why it has so many tight curves - not wanting to purchase too much land). With the result that using the bypass is not much faster…

Sometimes roundabouts are used to limit traffic speed, since you MUST slow down, while keeping the same flow (for the calculated traffic throughput). Maybe that was the purpose. Roundabouts are generally more expensive than intersections due to needing more land works and more land than a normal cross intersection.

I don't know if that was the purpose or just a side effect, but I would have thought that the purpose of a bypass is to provide a more attractive route than the one going through the town center (so motorists have an incentive to use it), and having to slow down at the roundabouts (along with the mentioned tight curves and the 60 km/h speed limit) completely destroys the attractivity.
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