On the roundabout

[Rob Tucker]

The highway department brought in a national expert on roundabouts a few years ago. He explained that the public easily gets trained on using one as the roundabout is being built and traffic is slowly routed around it during construction. By the time it is completed everyone knows how it goes.

[hotinhawaii]

That's a good point Rob. I hadn't thought about that. People will be using the roundabout in a controlled way for months.

Greg, your comment still has me concerned though. Suppose that tomorrow I decided to ignore green lights because I thought it was more polite to let those stopped at red go. And suppose that many people started following my lead and stopping at green lights to show aloha to those at red. And suppose further that you were new to the island. Would you just jump on and ignore the meaning and intent of the signals just because others were?

[Greg]

Huh? Stop lights? [:p]

Here's how I deal with the Kea'au merge;

If I'm in the left lane, I relax, loosen up, leave a gap between my car and the one in front of me, let people from the right lane merge.

If I'm in the right lane, I relax, loosen up, leave a gap between my car and the one in front of me, merge left at the end like everyone else.

The problems are caused by drivers that bunch up to prevent merging. It's perfectly legal and sensible to stay in the right lane until the end.

I don't really agree with your interpretation of merging. In all my years of freeway commuting there never had to be a sign that said "zipper", akamai commuters just zip. If we're to become a commuting culture here, people will eventually figure out how to do it sensibly. Feel free to follow my lead! Merge and let merge. [8D]

[DTisme]

quote:

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Originally posted by Greg

The problems are caused by drivers that bunch up to prevent merging. It's perfectly legal and sensible to stay in the right lane until the end.

I don't really agree with your interpretation of merging. In all my years of freeway commuting there never had to be a sign that said "zipper", akamai commuters just zip. If we're to become a commuting culture here, people will eventually figure out how to do it sensibly. Feel free to follow my lead! Merge and let merge. [8D]

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"Merge and let merge." Love it. Mahalo! - well said.

[DTisme]

quote:

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Originally posted by james weatherford

quote:

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Originally posted by DTisme

[quote] in Washington, D.C., where roundabouts go back to L'Enfant's original 1789 design.

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No, those ARE NOT ROUNDABOUTS IN D.C.
Those are TRAFFIC CIRCLES and NOT the same as roundabouts.
Design of splitter islands and yield on entry are basic differences.

Same for the "merge" bit above -- that IS NOT what happens at a roundabout.\

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{insert plethora of links}

a) please don't yell.
b) Of the few links you posted that worked (double-checking links would have been nice; but that's ok, I have time)... this one was the most helpful: http://cityofdavis.org/pw/traffic/roundabouts.cfm

Sorry - don't really see the difference. Car enters roundabout or traffic circle, goes counter-clockwise, exits. Is the difference, then, of scale? Are roundabouts only one-lane? All the samples seem so. Note the photos in the links of successful roundabouts. They seem to be in neighborhoods, not major thoroughfares. Therefore, they seem perfectly suited imho to present 4-stop intersections in HPP and Nanawale, but not on 130, which handles a lot more traffic.

On the differences you've stated: My understanding is that there is yield on entry on traffic circles. You can't just willy-nilly enter the circle. Plus, not all circle entrances have splitter islands, but many do.

(corrected sentence order for clarity)

[Bob Orts]

quote:

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Originally posted by DTisme

Sorry - don't really see the difference.

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Traffic Circles are not Roundabouts. Roundabout function in a very specific way and that functioning is by far the best method of traffic control at an intersection. That is a given and undisputed fact.

But the slight of hand magic trick is many Traffic Circles started out as Roundabouts but failed. As they failed, additional measures or design features had to be installed to correct the problem and as a result they changed from Roundabouts to Traffic Circles. Since they are no longer technically Roundabouts, you can't use them as examples of Roundabout and have to use them as examples of Traffic Circles. Notice how only some Roundabouts are mentioned even though more Roundabouts have been constructed. That’s because if the Roundabout was a failure and changes had to be made to avoid a total screw-up at that location, everyone claims you can’t use it as an example because it’s no longer a Roundabout, even though that was what it was initially, and it is technically a Traffic Circle. So, you can’t argue about the negatives of Roundabouts because there are no bad Roundabouts, only bad Traffic Circles (it’s all taken care of through the magical name change game).

[DTisme]

Lesson learned, but the distinctions are really minute.

Wikipedia did a good page on it: http://en.wikipedia.org/wiki/Roundabout

Check this out: http://en.wikipedia.org/wiki/File:NonUK_...8_Cars.gif but imagine every little car colored car is pulling another little colored car with a rope.

I like the versions with the total bypass around the thing ("separated side lanes") http://en.wikipedia.org/wiki/File:DiamondRoundabout.jpg

[Bob Orts]

quote:

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Originally posted by DTisme

Lesson learned, but the distinctions are really minute.

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There is really only one distinction:
If it's built as a Roundabout and works as a Roundabout it's a Roundabout. If it's built as a Roundabout but fails as a Roundabout it's a Traffic Circle. []

[Kapohocat]

quote:

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Originally posted by Greg

I agree. It should be a zipper lane. It is a zipper lane. People are learning to navigate this bottleneck on their own. All that's missing is the correct wording on the sign.

What's amazing is that in spite of there being two essentially equal volumes of cars obviously merging in an alternating fashion, there's still the occasional driver determined to block out the right lane.

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I agree!

The zipper merge seems to work a lot better than the signs instruction at the merge by KHS. In larger cities there is actually a green light/red light for the same effect (with big tix for jumping the light). Here in Puna, we have some intelligent drivers who on their own figured out what works best despite the best intentions of the engineers to interfere.

[hotinhawaii]

Has the whole world gone mad? It is not a zipper merge. The signs clearly say "Merge Left." Just because you think a zipper merge would be better and some people act as though it is does not make it so. If I decide a stop sign should not be there and so I just run it every time does not make it go away! Does your line of thinking mean I can choose to make it a "Merge Right" lane? How about if I interpret it as a stop sign?

I think the main issue is that the majority of people do not know what it means to "merge left". While the Hawaii Drivers' Manual does not specifically define merging, it does detail how to enter a freeway which is the same procedure as merging.
• Observe traffic in the entrance lane. If it is congested, slow down or stop near the
entrance (see illustration). DO NOT MOVE SLOWLY TO THE END OF THE
ENTRANCE LANE AND STOP. It is very difficult and dangerous to attempt
to enter freeway traffic when you are stopped at the end of the entrance lane.
• When the entrance lane is clear, use your turn signal to indicate that you are
going to merge into the freeway traffic lane; then increase the speed of your
vehicle to match that of the freeway traffic.
• Look to see if there are any oncoming vehicles in the freeway near lane. If not,
move into the freeway near lane and maintain your speed. If there are oncoming
vehicles, slow your vehicle slightly and move in behind the oncoming vehicle.