In an article that acquired well over 300 replies on the normally-subdued Ars Technica comment board, it was reported that the Zipper Merge is the safest and fastest way for two lanes of traffic to merge.
The Zipper Merge is the polite name for those "rude" drivers that cruise to the head of the soon-to-be-closed lane and then merge with polite drivers at the last minute, cutting off and "delaying" all the polite drivers who moved to the remaining lane as soon they see the lane reduction signs.
Minnesota, and Washington state have found after extensive study, that having drivers filling both lanes and taking turns merging right at the point of closure was more efficient and safer than any other method of handling a lane closure.
Both states now officially endorse this method, but have a lot of driver re-education to do.
Washington state has a ways to go to catch up to Minnesota's efforts [PDF], however. In particular, the Minnesota Department of Transportation has added sensors to key roads; when they recognize pile-ups and congestions, electronic signs turn on and tell drivers to fill both lanes and merge at a later point.
MnDot has also provided a YouTube video to show how it should be done.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @04:33PM
People have FINALLY started to figure this out in Silicon Valley
Unfortunately, at the same time traffic volume, especially on the CAL 237
corridor has gone non-linear.
I don't want to even think about how that commute is going to suck once the
Levi's football stadium that replaces Candlestick opens in Santa Clara.
(Score: 5, Insightful) by FakeBeldin on Friday July 25 2014, @04:39PM
As the Ars article explains, "zipper" merge is merging at the end. It does not help against rude drivers - in fact, it requires good behaviour from *both* lanes to function well: one car from left, then one from right, then from left, etc. Sort of how a zipper works (who'd've thought that? ;-)
Racing through to the end and wedging your car in is definitely not the idea - just as having two teeth on one side go through your zipper wrecks havoc to your fly.
As the article also states, this works well when it's busy. On quiet stretches, merge early works best.
(Score: 4, Informative) by BasilBrush on Friday July 25 2014, @04:53PM
Indeed. Zipper merge is not "the polite name for those "rude" drivers that cruise to the head of the..." at all. Those are still assholes.
Zipper merge is where there are signs to indicate that everyone should stay in lane until told to merge in turn. In the UK they call this "filter by turn".
Hurrah! Quoting works now!
(Score: 3, Informative) by Nerdfest on Friday July 25 2014, @05:22PM
Absolutely. The trick is also matching speed. Assholes cutting people off and making them hit their brakes if what causes the delays more than anything. I remember seeing a video of 20 or 30 drivers told to drive at a constant speed in a circle. In a few minutes, there was points where they had to stop. People don't watch far enough ahead and have to hit their brakes because of it and this is always amplified when people are not looking ahead or following too closely. Zipping up to the end is not the answer. When the people rush up and hit their brakes to match speed at the end that compression wave happens. The parent post is correct. Stay in the lane. Zipping up to bypass the bottleneck (generally caused by assholes) just causes more bottleneck, and congratulations, it will eventually happen in both lanes.
(Score: 1, Insightful) by Ethanol-fueled on Friday July 25 2014, @06:27PM
I deal with the problem by driving between both lanes before they merge so assholes can't try and pull all the way up to the right and butt-in. Sure, I get a lot of angry honks, but there's not a goddamn thing they can do. Serves 'em right for not having any patience. If I won the lottery I'd get an obnoxiously wide beat-up dually [ncspecialties.com] truck and block jumpy impatient assholes all day.
(Score: 2) by Geotti on Saturday July 26 2014, @12:41AM
If I you do that around here, you'll just have your license revoked after eight times someone reports you. Please come visit!
(Score: 3, Interesting) by Nerdfest on Saturday July 26 2014, @03:22AM
I do the same. I actually did it to a cop in an unmarked once ... he hit his lights and went around. I actually signal, change to the open lane, then signal back and hold my position by the empty spot. Legal , and stops the compression wave in the continuing lane. Also annoys douchebags, so added bonus.
(Score: 3, Interesting) by mojo chan on Friday July 25 2014, @09:47PM
I find the best thing to do is pull into the short queue but then match speed with the longer one. If the longer one stops, I stop too. That way queue jumpers are blocked and fairness ensured. It's also quite funny watching the arseholes behind going nuts, flashing their lights, and gesticulating wildly.
const int one = 65536; (Silvermoon, Texture.cs)
(Score: 2) by Geotti on Saturday July 26 2014, @12:43AM
Who the fuck do you people think you are? Are you a fucking mind-reader? What if someone needs to get to the hospital and you're blocking his way? I'd punch you all night for pulling off shit like that.
(Score: 2) by BasilBrush on Saturday July 26 2014, @05:30PM
I'm pretty sure they'll give way for ambulances. Assholes flashing their lights or noking their horns in cars to get past are not in life and death situations, they're just assholes.
P.S. Your keyboard warrior threats are laughable, and confirms your asshole status.
Hurrah! Quoting works now!
(Score: 2) by Geotti on Saturday July 26 2014, @08:14PM
Oh, so in your opinion all emergencies enjoy the privilege of having emergency-lights, Mr. Know It All?
You can stick your ad hominem back where it came from.
(Score: 1) by darkfeline on Saturday July 26 2014, @12:34AM
>Zipper merge is where there are signs to indicate that everyone should stay in lane until told to merge in turn.
That's deceptively false. Zipper merge is where everyone evenly distributes themselves between the two lanes. The point is that it is often considered rude to change to the near-empty soon-to-merge lane since you are "cutting in line", but that it is in fact more efficient if half the cars "cut" to the soon-to-merge lane.
Join the SDF Public Access UNIX System today!
(Score: 2) by BasilBrush on Saturday July 26 2014, @05:25PM
It only works if singed as that. Individuals doing this unilaterally are not only assholes, they cause congestion by other cars having to take evasive action.
Hurrah! Quoting works now!
(Score: 2) by frojack on Friday July 25 2014, @04:58PM
Actually that IS the idea, and the drivers in the continuing lane are at fault for not allowing the merge, or actively trying to prevent it.
Part of the problem is that the laws about merging vary from state to state. That is why it will probably take a decade for this to become the normal mode of handling lane closures.
No, you are mistaken. I've always had this sig.
(Score: 2) by isostatic on Friday July 25 2014, @10:35PM
Shush, I'm quite happy for people on a 4 lane road to queue up in the inside lane for 3 miles while people like you and I travel up to the end.
(Score: 2, Interesting) by anubi on Saturday July 26 2014, @01:27AM
I agree that the zipper-merge looks like the most efficient model - but what I am afraid of is what if I now have no option and *have* to merge - because I am now at end of lane going 40 MPH, and the guy in the other lane won't let me in - and my other option is hitting a big concrete barrier?
If I see beforehand that my lane is going away, I try to get over while I can while I still have the option to delay.
Its a tragedy of the commons thing. Somebody may want to see me hit the big concrete barrier just for the fun of it, or die trying to merge my little car in front of his truck. Once I stop because I can't merge, then its like a jammed zipper.
If one is going to have these zipper merge spots, at least have a camera on them so if anyone deliberately causes another car to ram the barrier, all kinds of financial hell can be placed on the asshat that fouled up the merge...
I hate zipper merges on freeways. To me they are an indication of really poor design. A lane should never just end, but it is quite acceptable for it to peel off as an offramp. That way, an unsuccessful merge left only leaves one having to re-access the freeway from the side road, not ambulances and wrecker trucks.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 2) by frojack on Saturday July 26 2014, @05:47AM
There is this pedal, just to the left of the gas pedal.
Try pushing that some time, and surprising things happen.
No, you are mistaken. I've always had this sig.
(Score: 2, Insightful) by anubi on Saturday July 26 2014, @06:19AM
Kinda obvious there... I end up stopping... while the lane I am trying to merge into is going maybe 40MPH.
I have a low powered car, and even those stoplights they put at freeway onramps provide a problem for me, as often I find myself trying to merge into 60MPH traffic when I could only get to 40 or so. I guess thats a nice thing about working for the government - if I put up a pool and a kid drowns in it, I am liable, but if I work for the government, put up a stop light, then expect people to stop then accelerate up to merge speed in a couple of hundred feet, but they do not succeed and get killed or maimed so they could obey my little light, so be it.
The problem is once I lose velocity, merging becomes just that much more difficult. If I merge before I have to , I have the option of not merging if I do not think I can do so safely... but if I wait for the very end, I am at the mercy of someone else to "let me in", and experience has taught me there are a lot of drivers out there who would just as soon see me hit the pilings. A lot of people completely change once they get behind a wheel.
Not all, but a very small percentage is all it takes to send me to the hospital.
Yes, I know about that law about if you hit a car behind the door or something like that, it is automatically the rear driver's fault, but I have no intention of pitting the laws of man against the laws of physics. If it looks like a collision is imminent, I will chicken out and not force the issue. Besides, I have noted that the worst ones are usually quite rich people and they have ways of buying their way out of a legal jam.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 1) by danmars on Friday July 25 2014, @05:02PM
It does help against rude drivers, by decreasing the potential benefit to rude drivers. If the two lanes are equally full, there's nowhere for the rude drivers to zoom ahead in line. They can move up at most 1 position at the merge point, instead of dozens or hundreds of positions ahead of the courteous drivers. By lowering the incentive to be rude (they can save at most a few seconds instead of multiple minutes) a lot fewer people act that way, and everyone gets more equitable treatment.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @04:48PM
In Germany, that behaviour is demanded by law exactly because it's the most efficient.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @05:07PM
(citation needed)
(Score: 0) by Anonymous Coward on Friday July 25 2014, @05:27PM
See http://de.wikipedia.org/wiki/Rei%C3%9Fverschlussverfahren [wikipedia.org] - translation to English: https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fde.wikipedia.org%2Fwiki%2FRei%25C3%259Fverschlussverfahren&edit-text= [google.com]
(Score: 0) by Anonymous Coward on Friday July 25 2014, @09:19PM
Thanks for finding a mention of it. I couldn't before. I can read German, and there is only a requirement to "let people enter where their lane ends", not a requirement to do so. In fact, on the Wiki page, there even is a sign to remind people not to merge now, but later.
(Score: 0) by Anonymous Coward on Saturday July 26 2014, @05:31AM
a requirement to let other people merge, not a requirement for yourself to actually merge only at the end of the lane. But the most populous state is enforcing this scheme by means of temporary no lane changing markings up to the merge point.
(Score: 2) by Geotti on Saturday July 26 2014, @12:59AM
http://dejure.org/gesetze/StVO/7.html [dejure.org] Article 7, paragraph 4 of the StVO.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @06:27PM
In Russia, road zips you!
(Score: 2) by Silentknyght on Friday July 25 2014, @04:59PM
Having lived in MN for almost a decade---yet having grown up & driven elsewhere---there are some serious driving/traffic issues here. The interstate system is still two lanes each way in most places, and some of the most congested places are so because of some truly ridiculous lane inter-weavings.
That said, please note that this statement appears to be for "when a lane is closed ahead."
In several places I can think of several places---especially the entry to the Lowry Avenue Bridge from east-bound I-94---where there is substantial traffic backup trying to access a single-lane on/off ramp. Of course, in these cases, you have impatient jerks who try to speed to the front of the line by using the next lane to the left, a lane which doesn't 'close'. Most of the time, they quickly decelerate from 55+ to 5-10 mph as they have difficulty finding a spot to cut in line.
The statement appears to suggest that such actions are unsafe and are not condoned.
(Score: 1) by Adamsjas on Friday July 25 2014, @05:16PM
Minnesota is also the state where red-light chaining was invented.
That's when the light turns red but drivers simply continue to chain through the intersection bumper to bumper, blocking cross traffic because they don't want to wait for the lights to cycle. In some places in Minneapolis it got so bad at intersections near large plants at shift change time that they they had to station police at key intersections to prevent the practice.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @05:49PM
But but but according to my wife and father-in-law who lived there 40 years ago they have da best drivers evar!!!
Like all these sorts of schemes they depend on only good behavior. You have been sitting in this hot car with the broke AC for 3 hours and you are the front finally oh let someone in. That is not human nature. That is a recipe for road rage. Just add impatient jackasses. If people would properly yield and let others in this could work. If you get one line jamming the breaks all the time it creates a standing wave.
It probably maximizes thruput of cars. But not wait time in cars.
The best thing I have seen is truck drivers who straddle the line and MAKE those behind them line up instead of lining up at the last second. Dangerous as hell but it works.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @06:15PM
This sort of shit was from Minnesota!? I've been seeing it A LOT here recently in the Silicon Valley and I just attributed it to all the foreigners who grew up in a culture lacking in courtesy and law abiding. Yeesh.
(Score: 4, Insightful) by mhajicek on Friday July 25 2014, @06:01PM
I'm a Minnesotan. There's a place (hwy 100 southbound) where five lanes merge down to two plus an exit lane.
My wife and I took a road trip to New York a few years ago
it's amazing how east of Chicago people actually know how to drive. Do they do drivers ed different there?
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by evilviper on Saturday July 26 2014, @05:52AM
Congestion causes natural selection. You either get very good at driving quickly, or you burn through tons of money and medical bills, which keeps you off the road.
Hydrogen cyanide is a delicious and necessary part of the human diet.
(Score: 2) by emg on Friday July 25 2014, @05:57PM
And, believe it or not, 'zipper merging' worked.
However, it worked because it was such a disaster on the first couple of days with no-one wanting to let anyone else in that most drivers then switched to alternate routes until the construction was complete.
(Score: 5, Insightful) by Bob9113 on Friday July 25 2014, @06:36PM
The Zipper Merge is the polite name for those "rude" drivers that cruise to the head of the soon-to-be-closed lane and then merge with polite drivers at the last minute,
No, it most certainly is not. Zipper Merge is when both lanes are filled equally by all drivers and the merge zippers right at the end. Zipper merge is more efficient than early merge, but, as the study clearly points out, it is only superior when everyone is doing it. If the social norm is to merge early, people flying past does not achieve the improvements that make zipper merge more efficient overall, and it also leads to more accidents.
Read the study more carefully. Don't leap to harmful and incorrect conclusions just to get a provocative headline, or to justify your sociopathic behavior.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @06:55PM
Actually, that sounds like anti-social negative assumptions about others. What are you, a sociopath? If people are early-merging, you can also look ahead at the traffic and the behavior of different drivers, and drive ahead to merge near good drivers, who will naturally make room without excessive slowing.
Haters hate, you can't help it, I know. But stop thinking that learning the word "sociopath" makes you a special flower.
(Score: 2) by kaganar on Friday July 25 2014, @06:55PM
When I moved to southern California I thought everyone drove like assholes (eventually including me). Then I moved to a much smaller town and found people drive unpredictably. I miss the assholes, now, I had been in no accidents and felt much safer because I knew what was going on and how to respond. Not so anymore.
In general, ambiguity in driving scenarios leads to an increased chance of accidents. Like any activity practiced by humans, repetitive and well-defined actions are the most reliably learned and performed.
Driving is high-risk, but in the U.S. we treat it like it isn't:
My certified accountant is required to receive annual education so she doesn't put me out of $10,000 accidentally. However, we are all relatively likely to cause an accident leading to $100k+ damage and/or injury, but we probably will only ever have meaningful contact with the roadway authorities when we do something seriously wrong (too late) or if we're considered an "old" driver and need to undergo re-examination.
(Score: 2) by strattitarius on Friday July 25 2014, @08:43PM
Slashdot Beta Sucks. Soylent Alpha Rules. News at 11.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @09:57PM
I moved from a small town to a big city. What you find is that roads in big cities are designed to move people (crazy as that sounds) where as smaller towns are not engineered for traffic flow. In really large cities, they actually try to measure effectiveness of a road. Some cities like Dallas will destroy a pretty good road to improve on the design which will lower mortality rate or increase flow. Think about this, you cant have a stretch of road in a big city flowing X00k people a day with numerous pile ups. The cost to that local economy shutting down a road daily due to accidents would be too much and unacceptable with X deaths per million miles traveled. In a small town, no one ever gets X million miles so it doesn't matter how safe unsafe a stretch of road is - they just put up 5 mph speed limits. F them small towns.
(Score: 0) by Anonymous Coward on Friday July 25 2014, @10:11PM
Exactly, I come from southern California and it confuses me when someone driving in low-traffic stops in the middle of the road (being "polite") to let someone turn. Where I'm from, this is only saved for high-traffic situations where it would be incredibly difficult for a car to turn onto the road. Somehow, forcing all traffic (behind the "polite" person) to go from 45mph to 0mph in order to let one person in is better than 4 cars passing then the car turning when there is an opening.
Also, W[hy]TF do people get mad when you pass them (speed-up/honk)? Do they not understand what the broken line means or do they think they are fighting the War on Speeding?
P.S. It boggles my mind that pedestrians will wait for cars in both lanes to stop before stepping foot in the cross-walk.
(Score: 3, Informative) by evilviper on Saturday July 26 2014, @05:49AM
In my observations, it seems to be a question of congestion. Even in Southern California, if you drive late at night, or into light traffic areas, you see the same change in behavior.
People who are driving in lower-traffic areas for some time, apparently grow blase about signaling, checking their blind-spot, etc, etc., or they're just less attentive to it, and their brain doesn't process the small car they can only see a slender top of in their rear-view mirror.
Personally, I still greatly prefer driving in less traffic. With greater distances between cars, comes greatly reduced chances of rear-ending in a sudden stop, and you can safely reduce the amount of painstaking attention you put into the job, making it far less stressful, as long as you don't go quite as far as those afore mentioned unpredictable bad drivers.
Hydrogen cyanide is a delicious and necessary part of the human diet.
(Score: 2) by Adrian Harvey on Friday July 25 2014, @10:41PM
It's so known here in New Zealand that it's part of the road code [nzta.govt.nz] (traffic rules / drivers ed to non English speakers) and has been for years. There's road safety campaigns based on it and billboards that say "Merge like a zip!" . Nice to see the rest of the world catching up...
(Score: 2, Informative) by jbWolf on Saturday July 26 2014, @12:45PM
The book Traffic [amazon.com] by Tom Vanderbilt came to same conclusions and has a lot more interesting stuff too. He specifically talks about culture and the design of the road -- both play a huge part of how safe driving is. For instance, he makes an argument that fewer (if any) signs are best or that raised sidewalks aren't any safer that sidewalks that are flush with the road. One road engineer showed Tom how safe his design of the road was by closing his eyes and walking backward across the street with traffic safely passing him. Very interesting stuff.
Tom did a lot of homework. The version of the book I have is 383 pages long (not counting the index). From pages 293 to 383 are only notes supporting the rest of the book -- almost all notes are further descriptions of where he got his information including Internet links, newspapers, magazines, etc.
www.jb-wolf.com [jb-wolf.com]