Keaau Bypass Merge

[KeaauRich]

Greg is right...if both lanes travel at the same speed up to the merge point and then merge zipper style, traffic will flow more freely with less backup then if everyone merges left prematurely (which would only push the backup further back towards Hilo).

[JohnS]

Aloha,

Traffic studies have shown that the "zipper" merge some have mentioned is usually the most efficient, when people cooperate. IIRC there's even some info on this in the Puna CDP documents somewhere.

That is, a merge where the two become one with some aloha is actually better than everyone trying to merge early.

When it doesn't work (jams up) is when the right laners are trying to push in ahead and the left laners are trying to keep them out.

And, ditto that when two lanes go to one there will be a slowdown when traffic is above a certain quantity. No way around that except changes in land use and zoning and work schedules and so on so that less people have to commute, and less at the same time.

By urban standards it hardly even qualifies as traffic... :-p

[hotinhawaii]

Let's all be clear about this: the right lane is now designated as a "merge" lane, not a zipper lane. A zipper lane would have a sign saying something like "alternate merge." Judging from the responses from thoughtful people here, there is confusion regarding what "merge" means. A merge lane means that those in that lane yield right of way to those in the lane of travel. When there is an opening, they should gain speed and merge into moving traffic at the same speed. This merge lane would work in lighter traffic if people knew how to use it but clearly they do not. In heavy traffic, the merging concept can't work because everyone is stop and go. Furthermore, the merge lane can't work in that location because almost no one seems to know what it means!

I think the best, cheapest and easiest solution now is to designate those two lanes as zipper lanes with new signage. However, I don't think the phrase "alternate merge" is going to mean anything to people since they already don't know what merge means. Surely there must be some more succinct signage out there for designated the zipper flow.


At some point soon, work is going to begin on widening the highway from the merge location to Shower Dr. Once that begins, traffic will just be completely gnarly until that is completed. But there is some hope for the future.

[Rob Tucker]

All of the merge area is very soon due to become much, much more complicated. The contracts for the construction and widening of Hwy 130 from the bottle neck to Shower Drive should have been let. I expect on site work to begin soon. Once it starts we all are in for what looks like eight years of almost nonstop construction.

What we deal with now will be quickly become The Good Old Days.

[lomaxArtz]

I live in Santa Cruz, CA. We just have merges here. Most people are cooperative, some just have to be first no matter what. Our Hwy 1 gets very crowded at commute time, often taking 30-45 minutes to go 7 miles. Unlike Puna, we can somewhat drive through town instead, but it is still very slow.

When I drive through San Jose, there are red lights/green lights for merging. I don't know the road all that well, but those lights seem to help a lot. I vote for lights[].

[mdd7000]

quote:

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Originally posted by Rob Tucker

...Once it starts we all are in for what looks like eight years of almost nonstop construction...

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That might just slow down the population explosion in lower Puna.

[DTisme]

This again. Didn't the plethora of letters to the paper put this stupid thing to rest? I'm a firm believer in the efficiency of a zipper merge. left right left right, at the point of the merge, not before. Go to http://ops.fhwa.dot.gov/publications/fhw...ciples.htm -- scroll to #3, zipper merge. Stay in your lane, merge when it's time.

ps Aloha to IomaxArtz - you're from my old digs. We had an efficient zipper merge in Half Moon Bay, too.

[DTisme]

I've never seen a sign that says "alternate merge" or "zipper merge" in Hawaii. The "land ends" sign is, I believe, all Hawaii uses. Maybe we should petition the state to start. "Zipper Merge Ahead, 300 ft"? Love it. Traffic engineers for years have recommended L R L R merges. It's the signage that sucks. The notion that there is a right-of-way here (i.e., the "thru lane") is what confuses people. When people move from the left lane before the Keaau bottleneck to the right, they aren't trying to "take cuts," they are trying to move the traffic more efficiently. It's physics. Google "zipper merge" and see what you come up with.

[TrevorKane]

I've never seen a "zipper merge" sign, but the L R L R method at the point of merge does work best in my experience.

On Houston freeways, on weekends, you can see what happens when people get in line early. There is typically a line of 30-50 cars at a backing up exit ramp, and those cars at the end of the line can take more than 30 minutes to get off the ramp. What's happening is that people drive by the line and cut in line near the front - so much so that about 80% of the cars getting off the ramp are cars that have cut into the line. So, the people in back who don't do the cutting in line wait while people cut in front of the people who have cut in front... 1-2 minutes to get off if you cut, 30+ if you don't. Wonderful choice, at a glance it looks like most people don't cut, but watching it long term, you can see that most people do, in Houston.

At a 2 lane merge, you can attempt a "vigilante save" of the early mergers by staying in the empty lane at the end of the line, preventing people from cutting by just staying with the person who was there before you - this works with moderately aggressive traffic, but extreme yahoos will go around you on the shoulder...

Better still if everyone would just choose the shortest line until the dividing line is gone.

[Bullwinkle]

or fix the road.............. we really need a couple of lights indicating which lane has the "turn" to go

ramp metering is a good example