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Old February 28th, 2012, 11:08 PM   #621
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Quote:
Originally Posted by tradephoric View Post
Here's an example of how heavy pedestrian traffic can create gridlock inside of the roundabout. This is a partial 3-lane roundabout constructed next to a high school in Kitchener, Ontario Canada.

For probably 30 minutes out of the day (15 minutes during school let in, and 15 minutes during school let out) the roundabout loses its effectiveness. Here's another video about this particular roundabout dealing with pedestrian safety:
The solution is as easy as placing an on-demand traffic light that turns green for pedestrians once the button is pushed and after waiting several seconds so that more pedestrians pass together.
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Old February 29th, 2012, 12:43 PM   #622
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No, Belgians have indicators as well. They may not always use them, but I've definitly seen indicators on Belgian cars.




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Old March 1st, 2012, 10:05 PM   #623
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Red car on picture is almost surely going out of the roundabout on next exit -

This is typical case of a roundabout with three lanes, which almost all the time functions like an one-lane roundabout. At least 30-50% of drivers make it so.
This is just lazy roundabout design though. It's more than 2-lanes wide, so the lanes should be spiralling rather than concentric.
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Old March 2nd, 2012, 10:28 PM   #624
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Quote:
Originally Posted by Chilio View Post
Red car on picture is almost surely going out of the roundabout on next exit -

This is typical case of a roundabout with three lanes, which almost all the time functions like an one-lane roundabout. At least 30-50% of drivers make it so.
Its a bit of a silly design as the roundabout has 3 lanes, but there are only 2 turning lanes from each junction to get onto it...

Sheffield (UK) has several good examples of 3 lane roundabouts...

The junctions have atleast 3 turning lanes, but here you can see that one of the roads has 4 lanes, the ones closest to the left is for left turns only with the other 3 directed for the roundabout only...

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Old March 3rd, 2012, 03:45 AM   #625
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That's a nice 3-lane roundabout in the UK! One thing i don't like about it is that the 4th left turn only lane seems to almost get squeezed out. Wonder if there are a lot of sideswipe accidents especially if there is a lot of large truck traffic. Do you think the left turn only lane adds a lot of capacity to the roundabout?
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Old March 3rd, 2012, 10:41 PM   #626
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Quote:
Originally Posted by tradephoric View Post
That's a nice 3-lane roundabout in the UK! One thing i don't like about it is that the 4th left turn only lane seems to almost get squeezed out. Wonder if there are a lot of sideswipe accidents especially if there is a lot of large truck traffic. Do you think the left turn only lane adds a lot of capacity to the roundabout?
The design of arrows on approaching lanes of roundabout is very dangerous and ambiguous. As i said before arrows have to be like this:

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Old March 4th, 2012, 12:41 AM   #627
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^ In Australia, and presumably the UK, those arrow designs would do more harm than good. What's already there makes far more sense.
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Old March 4th, 2012, 05:45 AM   #628
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Here's a nifty partial 3-lane roundabout in Metro Detroit:



I agree with Geor that a standard turn arrow is too ambiguous at a roundabout. Here's a closeup of the lane arrows used at this roundabout:

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Old March 4th, 2012, 12:06 PM   #629
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great roundabout I hate those old multiple-lane roundabouts, where nobody uses inner lanes
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Old March 4th, 2012, 01:32 PM   #630
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Quote:
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^ In Australia, and presumably the UK, those arrow designs would do more harm than good. What's already there makes far more sense.
In continental EU the things are different than in keep to the left countries. In Croatia there are also some old roundabouts with no circle in the middle of the arrows, but we are aware of the negative aspect of that and hope to change them in near future.
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Old March 4th, 2012, 01:37 PM   #631
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Quote:
Originally Posted by tradephoric View Post
Here's a nifty partial 3-lane roundabout in Metro Detroit:



I agree with Geor that a standard turn arrow is too ambiguous at a roundabout. Here's a closeup of the lane arrows used at this roundabout:


These are very nice pictures. That is what i wanted to draw. Thank you very much.
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Old March 4th, 2012, 02:53 PM   #632
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Quote:
Originally Posted by tradephoric View Post
That's a nice 3-lane roundabout in the UK! One thing i don't like about it is that the 4th left turn only lane seems to almost get squeezed out. Wonder if there are a lot of sideswipe accidents especially if there is a lot of large truck traffic. Do you think the left turn only lane adds a lot of capacity to the roundabout?
I've not really heard of any accidents related to that. I think the 4th lane just adds capacity for traffic that is waiting mostly. That junction does suffer from large ques. But the only thing that would solve that is a free flowing junction. Something that would never happen lol. Those roundabouts are large because the original design was for the ring road to continue under them in an underpass, the A61(M)
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Old March 5th, 2012, 01:24 PM   #633
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Originally Posted by geor View Post
In continental EU the things are different than in keep to the left countries. In Croatia there are also some old roundabouts with no circle in the middle of the arrows, but we are aware of the negative aspect of that and hope to change them in near future.
I think it's because in the left countries we say "continue straight the roundabout" whereas an American GPS would say "take the second exit at the roundabout." I really get confused by the navigation instructions when the second exit is not straight.
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Old March 5th, 2012, 01:38 PM   #634
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I think arrows are fine at standard 4-way roundabouts. Left, straight and right correspond to first, second and third exits respectively from the current location. Curly arrows add nothing and just look messy. Where the roundabout is more complex lane indications are provided by destinations, like V'RIA and K'DGE at Hyde Park Corner, nice and simple.

poshbakerloo: I don't think the left-most lane on your diagram is that bad - most people would go straight across the junction into the roundabout leaving plenty of room for left-turning traffic I'd imagine.
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Old March 5th, 2012, 06:46 PM   #635
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Quote:
Originally Posted by poshbakerloo View Post
I've not really heard of any accidents related to that. I think the 4th lane just adds capacity for traffic that is waiting mostly. That junction does suffer from large ques. But the only thing that would solve that is a free flowing junction. Something that would never happen lol. Those roundabouts are large because the original design was for the ring road to continue under them in an underpass, the A61(M)
Lane marking quality is severely lacking in the UK though. Those four approach lanes will be very narrow, barely the width of a car, let alone a truck and its been made worse by providing hatching on the median splitter. The UK has an obsession with hatching - maybe there's a huge volcano spewing naturally occuring white thermoplastic that has to be got rid of somehow - hence the boys from the Stevie Wonder school of white lining are put to work straight away.

I'd much prefer the Detroit style markings - neat and simple. Why does the UK way of doing things have to look like the effort of a 5-year old?
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Old March 5th, 2012, 08:33 PM   #636
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A study was performed back in 2007 entitled "Traffic Control Devices Pooled Fund Study: Lane Restriction Signing and Marking for Double-Lane Roundabouts" which compared fishhook arrows to traditional arrows.

Their conclusion was:

"The results of the present study showed no evidence of the Traditional Arrows inducing wrong way rotation, or of the Fishhook Arrows reducing wrong way rotation. Neither scheme produced any wrong way rotation responses in 324 trials each."

Of course the study also states:

"During training, approximately 450 single-lane roundabouts were driven by the 90 research participants (about 5 roundabouts per participant). These training roundabouts were presented before the main experiment in order to accustom the research participants to navigating through roundabouts in a driving simulator...During training for the simulation, one research participant did initially attempt to drive the circulatory roadway in the wrong direction. This participant quickly recognized the mistake, backed up slightly, and proceeded around the circulatory roadway in the correct direction."

A study of 90 participants who were allowed to practice correctly navigating a roundabouts before the test begin doesn't seem like a significant study.
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Old March 5th, 2012, 09:41 PM   #637
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Quote:
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I think it's because in the left countries we say "continue straight the roundabout" whereas an American GPS would say "take the second exit at the roundabout." I really get confused by the navigation instructions when the second exit is not straight.
IMO it is most important how to get there. As I said, this English example create very dangerous situation for EU Continental drivers as this type of arrows can lead them to wrong direction. On the other hand, the USA arrows have no ambiguous meaning.

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[COLOR=black][FONT=Verdana][COLOR=black][FONT=Verdana]For better understanding it is necessary to have additional similar vertical signs too



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Last edited by geor; March 6th, 2012 at 01:42 AM.
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Old March 6th, 2012, 12:30 AM   #638
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I am from continental Europe and i don't go to try to do your example.
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Old March 6th, 2012, 07:15 AM   #639
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IMO it is most important how to get there. As I said, this English example create very dangerous situation for EU Continental drivers as this type of arrows can lead them to wrong direction. On the other hand, the USA arrows have no ambiguous meaning.
[COLOR=black][FONT=Verdana]
I dnt see anyone trying to turn right on a UK roundabout unless they have a problem...
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Old March 6th, 2012, 09:46 AM   #640
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I am from continental Europe and i don't go to try to do your example.
You are a special case. This doesn’t apply to you.
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