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Washington, Minnesota officially endorse a “safer, faster” traffic merge

arstechnica.com

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Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#131

Post by greenyouse »

malandrew wrote: post #35

That video explanation made no sense to me. Basically the "interface" presented to the drivers has not changed, so why would drivers deviate from how they currently merge? Because the government said so? I don't see this working. However there are two solutions that could promote zipper merging: (1) Force both lanes to the center before moving that center lane to the side that is available ahead: ____________________…

Hey, I'm from Minnesota. Here is a merge spot that I take pretty often: https://www.google.com/maps/@45.008271,-93.203054,3a,75y,63....

Unfortunately, this spot still has lots of early merging. Some high traffic areas have special lanes for zipper merging, but I think the emphasis is on changing drivers' habits through public service announcements rather than redoing the lane structure.

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#132

Post by jrs235 »

jrs235 wrote: post #129
jerf wrote: post #19

Earlier quoted context omitted.

People think they are being nice. Education can work very quickly and efficiently on such people by showing them they aren't being nice after all. I live in the US in a "nice driver" area with a number of traffic circles. On a fairly routine basis I come up to a traffic circle and stop because there is someone in it coming towards me, but then they try to "helpfully" stop and wave me in, slowing down themselves, ever…

Someone died today because someone didnt know how to merge (the on ramp is to get up to speed) and probably because someone thought they'd be 'nice' and slowed down. My guess is both vehicles at the merge point slowed drastically and everyone on the interstate were too close to each other for the speed and volume of traffic. Sad. http://www.wxow.com/story/26101450/2014/07/24/breaking-part-... Edit: or perhaps we shou…

It sucks because the speed limit through there should probably be 40 not 55 when traffic is heavy. The problem then is people on the interstate still tailgate and/or don't leave adequate room to allow zipper merging.

Edit: to clarify, the slower speed should be that low only now during construction and lane closure.

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#133

Post by astrange »

adrr wrote: post #14

I thought the zipper merge was the standard way to merge? You stay in your lane till the merge section(end of your lane) and its every other car. Maybe its a California thing.

SF drivers are great at the waiting till the end of the lane part, but not about the letting you in. Sometimes I have to wait for three or four cars to go by before someone notices me.

Then again people also try to pass on the right by entering the merging-in lane and immediately getting stuck. More than once I've seen people try to pass inside the merging lane by going on the shoulder. Is it something about the 358i?

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#134

Post by tedsanders »

peeters wrote: post #76
justinpaulson wrote: post #61

Earlier quoted context omitted.

Zipper merging is only optimal if traffic is already slowed down dramatically. If traffic is still moving at any kind of speed, then early merge when there is space available will clear congestion faster than everyone driving up to the merge point and hoping that it works out.

No, it's provably optimal in flowing traffic as well. However, the "merge point" is variable depending on traffic speed. Obviously when you're going 100 km/h, the ideal merge point is significantly farther back than when it's stop and go. Nobody is saying you should wait until you're 20 feet from the barrier and then swerve into the other lane. But it's not like that's unique to this situation.

Zipper merge is synonymous with late merge: https://en.wikipedia.org/wiki/Zipper_merge

If you move the merge point back, then by definition it becomes an early merge, right? I don't understand your disagreement with what seems like a totally reasonable statement by Justin.

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#135

Post by malandrew »

wfjackson wrote: post #130
morsch wrote: post #118

Earlier quoted context omitted.

Good thinking. Apparently your option 2 was implemented (and considered an innovation) around where I live. Here's a picture from 2007: http://www.strassen.nrw.de/_down/pi-070322-03.jpg I don't know if they're still doing it. (Late merging has long been the default in Europe and is taught in driver's ed. However people seem to do it more reliably when reminded of the practice.)

I wonder if there's an option 3, install a mobile traffic light that allows one lane only at one time, in sequences of one minute or so each, i.e Alternating red and green lights, so that there is no need for merging. This way there's no slowdown caused by the merging, I feel that this method may actually make it faster overall. ____________________________________________ Green _ _ _ _ _ _ _ _ _ _ __________________…

Temporary traffic lights is definitely an interesting idea. It would however require a long barrier, otherwise, what is to stop people at the end of the stopped lane from trying to merge into the moving lane.

Another idea is a temporary speed bump in the lane that is not ending.

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#136

Post by blahedo »

wfjackson wrote: post #130
morsch wrote: post #118

Earlier quoted context omitted.

Good thinking. Apparently your option 2 was implemented (and considered an innovation) around where I live. Here's a picture from 2007: http://www.strassen.nrw.de/_down/pi-070322-03.jpg I don't know if they're still doing it. (Late merging has long been the default in Europe and is taught in driver's ed. However people seem to do it more reliably when reminded of the practice.)

I wonder if there's an option 3, install a mobile traffic light that allows one lane only at one time, in sequences of one minute or so each, i.e Alternating red and green lights, so that there is no need for merging. This way there's no slowdown caused by the merging, I feel that this method may actually make it faster overall. ____________________________________________ Green _ _ _ _ _ _ _ _ _ _ __________________…

Except that red means "stop", so presumably that whole "you don't have to stop" thing wouldn't work.

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#137

Post by mpyne »

sliverstorm wrote: post #121
mbrameld wrote: post #120

Earlier quoted context omitted.

How is it any more impractical than how temporary lane closures are currently done? It can still be done with cones or barrels and the end result is exactly the same.

The point is, suppose they are repaving the road one lane at a time. (Or, repaving half of a 2-lane road)

You simply move up the half-merge of each lane to suit. It's rather clearly explained in the diagram, where you can see it does end in one and only one lane actively in use. You'd do the "merge half of each lane" part while the road still supports two lanes, just as you already have to account for with current temporary traffic control devices.

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#138

Post by barnwell5 »

"Optimal" means different things to different people. What the DoT may be trying to maximize (safety, lack of frustration) is generally not what drivers want to maximize (overall speed) and I think there's confusion about that when zipper merge is discussed. The linked article uses the word 'faster' but the Minnesota pdf they cite actually says "Our analysis has shown that the Zipper System has no effect on travel time through the work zone."

Here is a Michigan DoT paper[1] from 2007 that analyzed zipper merge studies in various states and countries. Only 1 out of 6 showed statistically significant increase in throughput.

"It was found that the system did not increase the throughput or decrease the length of the queue." (Netherlands)

"It was found that the throughput did not increase, but the queuing was more efficient and there were less frustrated drivers." (UK)

"Beacher, Fontaine, and Garber (12) found that there was an increase in the throughput and a decrease in the queue length; however, the difference was not statistically significant." (Virginia)

"However, flow did not appear to be significantly affected by the dynamic late lane merge system." (Kansas)

"The data from both of the studies shows that the typical queue length decreased and the lane usage were nearly equal, but the throughput decreased slightly." (Minnesota)

"The results from Maryland’s deployment show an increase in the overall throughput, a reduction of the maximum queue length, and a more even distribution of volume between lanes."

1: http://www.michigan.gov/documents/mdot/MDOT_Research_Report_...

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#139

Post by sliverstorm »

mpyne wrote: post #137
sliverstorm wrote: post #121

Earlier quoted context omitted.

The point is, suppose they are repaving the road one lane at a time. (Or, repaving half of a 2-lane road)

You simply move up the half-merge of each lane to suit. It's rather clearly explained in the diagram, where you can see it does end in one and only one lane actively in use. You'd do the "merge half of each lane" part while the road still supports two lanes, just as you already have to account for with current temporary traffic control devices.

Ah. I see; I am not a very good ASCII art interpreter, is the problem.

Re: Washington, Minnesota officially endorse a “safer, faster” traffic merge

#140

Post by S_A_P »

wfjackson wrote: post #130
morsch wrote: post #118

Earlier quoted context omitted.

Good thinking. Apparently your option 2 was implemented (and considered an innovation) around where I live. Here's a picture from 2007: http://www.strassen.nrw.de/_down/pi-070322-03.jpg I don't know if they're still doing it. (Late merging has long been the default in Europe and is taught in driver's ed. However people seem to do it more reliably when reminded of the practice.)

I wonder if there's an option 3, install a mobile traffic light that allows one lane only at one time, in sequences of one minute or so each, i.e Alternating red and green lights, so that there is no need for merging. This way there's no slowdown caused by the merging, I feel that this method may actually make it faster overall. ____________________________________________ Green _ _ _ _ _ _ _ _ _ _ __________________…

I was driving in Atlanta a few weeks ago and was in a situation where two two lane roads converged to a single two lane road. Each side had this exact thing and it actually worked really well. Not the same as a construction zone but I think would be a helpful tool.
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