The Zipper Rule on German Roads
ozy.com
ozy.com
Also, having lived in Germany for five years and having been in 'Stau' for many times, Germans are also not terribly good/efficient at it. Typical problems: people switch to the lane that is supposed to zip when traffic is going faster, which is obviously counterproductive; and not leaving openings for people to zip.
It's probably still better, but it would be far more effective if all drivers would actually cooperate.
Just keep going for a bit further, use the whole road, and make sure you're matching speed with the rest of traffic, instead of making them (unknowingly) slow down to let you in. Also keep in mind you ARE allowed to overtake slower traffic on the on-ramp, so if there's a truck there, just pass it on the right, then merge.
Truck do have big powerful brakes, (newer ones with disk-brakes are really awesome) but it still takes a LONG time/distance to slow/stop 80,000lbs from 100km/h. Kinetic energy is a real bitch.
There are videos of new volvos with 'automatic emergency braking' that is impressive to watch; but that isn't real-world.
In the real world during a 'panic stop' the trailer brakes lock up and the trailer starts bouncing. If you are lucky the tractor wheels don't lock up, but while you have slammed on the brakes, you are still steering and trying to avoid hitting anyone.
316ft for a car vs 524ft for a truck.[1] Almost twice the distance.
And that does NOT match my real-world experience. I'd say on average it takes 3x-4x the distance to stop a rig.
[1]https://www.hg.org/legal-articles/stopping-distances-for-com...
While crashing can be catastrophic, I'd like to see some numbers on how many crashes into the backs of trucks were because the truck out-brake'd the smaller vehicle behind it as opposed to the smaller vehicle not paying attention.
One issue though is the same thing people have mentioned happens in the UK. Sometimes people just try really hard to stop you merging (large trucks seem especially guilty - maybe because many of them have driven from somewhere outside the NL). Most of the time I drive to the end and muscle in anyway, I think of it as expressing my newly approved "Dutch directness". :D
That's the issue with most of solutions to traffic though.
https://www.amazon.com/dp/0307277194
https://www.nytimes.com/2016/06/13/world/europe/a-london-sub...
Maybe it's cultural or depends on how eager to walk people are as to utilization factors.
https://sfist.com/2017/01/16/bart_says_actually_standing_on_...
Doesn't this depend on the walking/standing density ratio and walking speed/escalator speed ratio?
Let say the walking density is 1/2 of the standing density. If the walkers walk at the speed of the escalator (i.e. their speed relative to the ground is 2x the speed of the escalator), then the throughput is the same.
Optimal Tip-to-Tip Efficiency is well studied mathematically. Here's the authoritative paper: https://www.scribd.com/doc/228831637/Optimal-Tip-to-Tip-Effi...
There are other issues than eagerness to walk, like physical disabilities and collision avoidance. Ultimately two-speed traffic only works better if you're far from congestion, I believe.
I've stopped caring about other people's sense of fairness in these situations, and I always use the empty lane and merge late. The law is on my side, and people can glare and honk as much as they like. I just saved five-ten minutes of not queuing, they could too if they all learned to drive correctly.
All it would take would be a consistent change of sign showing merging in turn at lane-merge to change this behaviour
The odd thing is that you do see very occasional zip-merge signs in the UK, which tend to reinforce the idea that zip-merge should any be used in exceptional circumstance.
People here will follow each other incredibly closely, even at high speeds, and quite often they won't slow down to let you in if you're trying to merge.
The ruling was also applied inside the OLG Köln: 24.10.2005 - 16 U 24/05) but there are other courts that ruled like that.
(The same ruling applies to "Bundesstraßen")
I’ve been wanting a dashcam. Maybe it’s time to get one.
The problem with the Rettungsgasse is that you only need one idiot to screw it up, but you often get many.
When I enter a traffic jam, I see most cars building it properly, but then I see one or two cars ignoring all others. I can understand that people might forget about it right when they arrive at the traffic jam, but once everybody arounds you do it, some just don't seem to get what's going on.
In other countries, like Austria, the Rettungsgasse is formed on the rightmost lanes, while in Germany, its on the left most lanes. Disparity of rules across EU countries doesn't help here either.
Also, for some reason, once the first police car goes through the Rettungsgasse, I often see many cars that just stop building it. Like "good job everybody, the police went through, we don't need the Rettungsgasse anymore!" even though there is still a jam. The ambulance comes 1-2 minutes later, and it has to fight its way through because of all these idiots.
In Germany the problem with the idiots is particularly bad, because while there are a lot of German idiots on the road, you also get a lot of international traffic with their international idiots on the Autobahn. If you learned to drive in a different country, chances are that you haven't even heard about this, and learning about all the different traffic rules of all the countries you drive through is a PITA.
Minnesota[1]. Other states[2]. My home town[3].
[1]https://www.dot.state.mn.us/zippermerge/
[2]https://www.fleetowner.com/driver-management-resource-center...
[3]https://www.ajc.com/news/local/gridlock-guy-transportation-o...
I live in Ontario, Canada, and despite of our reputation for politeness, we have some of the worst/most selfish drivers anywhere. Part of this is because there doesn't appear (anecdotally) to be a lot of traffic enforcement, so people now push the limits as much as possible, whether it be texting while driving, running red lights, tailgating or merging improperly.
The only way I could see this work where I live is if there's strict enforcement to ensure it happens, otherwise you'll see behaviours like people not letting in mergers, or a second car trying to squeeze in after the legit merger.
Once, (in Pennsylvania) there was construction coming up, with maybe still half a mile until the actual cones to merge. This one guy in a massive truck didn't like that people were using both lanes so he straddles his truck across both lanes causing no one to be able to pass on either side.
Second, (in Colorado) there were signs that construction was coming up in a few miles, and the right lane would be closed. So, I was riding in the right lane, passing a massive line of cars in the left lane, getting flipped off the whole time, only to find out there was no closed lane. The signs just hadn't been taken down yet. So I was being flipped the bird because I was using a lane that was fully open.
I think people just don't like feeling that other people are "getting ahead of them", in life in general, and especially in traffic.
its like bandwidth. you are keeping twice the bandwidth up until the last possible moment, meaning the bottle neck is going to be "fed" as efficiently as possible with half the chance of causing a knock on effect elsewhere.
but this is not just a german thing.. in the UK there is a curved arrow sign on the road where one lane ends meaning "merge in turn"
you will also see signs saying: "use both lanes" and "merge in turn" (but as text) which are all the same thing.
you will often see it say after a junction or roundabout where maybe 200m later the road goes from two to one lanes. encouraging you not to just queue right through the previous junction and block that up too.
Once example I see often that is more length sensitive is dual left turn onto a highway onramp that merges to one lane before entering the highway.
If people use both lanes equally all the way to the merge point you can fit more cars through each turn light cycle and then the merging process continues even when the light has changed.
Often people merge early and leave room in one lane, which leaves some cars stuck on the other side of the traffic light who could have made it through.
I am German and can confirm that the zipper rule is holy here, but people often have problems following it, especially unexperienced drivers afraid of merging. Very often, there are additional signs to remind drivers of the rule [1][2][3].
[1] https://www.schilder-versand.com/assets/gfx/product/300x300/...
[2] https://upload.wikimedia.org/wikipedia/commons/thumb/e/eb/Hi...
[3] https://www.schilder-versand.com/assets/gfx/product/300x300/...
If you drive anything reasonably modern and not grossly overloaded/under-powered you can plant your right foot and be going traffic speed (or close to it) by the end of all but the smallest on-ramps. Most traffic is not made up of box trucks and panel vans so there is no technical limitation that prevents zipper merging on most on-ramps most of the time. Going close to traffic speed makes it a lot easier to merge but a lot of people aren't comfortable doing it that way.
Obviously people should zipper off before the light to load both lanes evenly and get as many people through the light before it cycles. Then after the light everyone should go forward and re-merge back into a single lane again.
Yet people will stubbornly pile into the left lane before the light leaving the right mostly empty then play games blocking people from merging in after the light.
Well, that's when they actually move through the light in a timely manner if not distracted from texting while stopped at the light :/
There is a long lane, often backup up past a stop light and then it goes to 2 lanes for about 50 yards before the light that lets you turn left onto the interstate.
Nobody ever turns from the rightmost lane, everyone stays in the left lane. When I use the right lane and pass people I get angry reactions, people trying to block me from merging back in, and a couple times people cursing at me and following my car.
Luckily I'm a big guy who's not easily scared.
So stupid.
I actually think that roadworks people could fix this fairly simply though without requiring people to think. Instead of closing one lane and keeping the other open, close half of each lane - create a new single middle lane, then people won't be able to queue in the "right" lane.
After everyone is in single file you can shift them wherever you want.
Here's what I mean: https://imgur.com/a/rCw4vJ7
I have also found that often on the motorway the lane isn’t really closed, so I have no intention of changing my behaviour.
I see similar things from time to time on a road I use frequently. In cases where it's very busy and both lanes fill up then merging in turn tends to happen quite well, but when there's only moderate traffic and it's queuing in one lane then events such as that you describe may occur. Perhaps some signs saying "queue in both lanes" and "merge in turn" at the appropriate points on the road might improve things.
In a recent construction on my way to work they put in two lanes where there was one, which must merge within a hundred yards to get over a narrow bridge. Filling both lanes and zipping would increase the capacity at that location, no doubt. But few drivers do it. Are others worried, as I am, that it would be part of a change in the overall driving culture, normalizing cutting ahead?
That is, could zipping be a local optimization that leads to a global suboptimization, an overall decrease in how reasonable it is to drive around here?
I suppose it's a matter of expectations. Originally from Portugal so I'm used to seeing far worse people driving on the road.
Conversely my mother lives near Worcester, and up there some of the drivers are insane. Nipping the wrong way round a roundabout, dashing across junctions on red. It's like they don't understand the concept of other traffic or sometimes even have actual control over the vehicle. Not everyone obviously, but enough to make my hair stand on end more than just once or twice.
You're not supposed to do that here (UK) except if you're already in slow moving traffic. You will fail your driving test for doing it. Not only that, but it's overall inefficient and causes traffic jams to form behind you if you slow down.
Like with people who hate zipper merging, sometimes what seems 'polite' isn't what's best for traffic.
I've had a car written off and had a very minor pedal bike crash due to people "being polite" and gesturing people out of side-roads when not safe to do so.
It needs public education to get people over this suboptimal behaviour.
On a tangential note, what's up with everyone everywhere saying "my God, drivers in [where I am] are the absolute worst"? They can't all be right.
I think people just adjust the scale to what they actually see. Deveoping countries with a new car culture are probably objectively worse, but not many people go there and see what it’s like.
This is like how it's pretty natural to let people out of a lift or a train before you enter, regardless of who waited longest. It's just not efficient to get people in before others go out. So we are tought to let people out first.
I think most of those people have not lived many places. My perception is that there are solid differences in driving culture between some cities. I found San Francisco traffic heavy, but with fairly courteous drivers. Vancouver same. Toronto was atrocious - lived there for ten years and never got used to the aggression and almost sociopathic attitude toward other drivers. Now I'm in Edmonton, where it's back to mostly OK - drivers here are a little more timid than other places but don't lean on their horn for every perceived slight or compromise the whole system to gain a 5 second advantage.
My completely unscientific take is that the most aggravating traffic comes when traffic gets dense enough to be a real irritant (I dunno - say maybe doubling a normal drive time between two destinations), but is still civil enough that most (say 90%) drivers are pretty polite and cooperative. That means that aggressive driving actually pays off, which makes it harder to take for people who don't zip past traffic in the turning lane only to forcefully merge back in.
but mostly people are not too keen to actually follow the rules.. i used to follow the pack, now i just follow the instructions and merge as late as possible. - probably this makes me an asshole
What happened in America? Has anyone studied the cultural driving differences and why they may be that way? I'm really interested in american road rage and the who/what/where/when/why if anyone has any good resources, I'd love to look at them.
Rather, people often try to avoid the ‘phase transition’ to a forced-merge flow-state for as long as possible, by ad-hoc merging earlier.
Partially that’s because the initial transition-to-zippering can be chaotic. Once established, zippering is easy to follow and well-respected. But, being the “first” to assert an alternating-right-to-merge depends on more judgement & recognition from a specific other driver.
It only leads to the perception of "cutting" when more idiots merge well before the natural merge point then logically where the lanes pinch back down.
If I see an opertunity to late merge I will often choose to stay in the late merge lane, but match speed with the traffic in the early merge lane, then zipper when I have to. People notice that I haven't cut anyone off or skipped the line, and people usually fill in behind me and I'm able to transform an early merge queue into a late merge queue.
You shouldn't late merge if it blocks a thruway. If a single lane highway has a backed up exit ramp then exiters should join the queue as soon as possible instead of late merging and blocking the highway.
Again an article making a generalization about the US without recognizing how large it is and the vast differing cultural norms and laws between states and regions.
The one thing that I have noticed is that people are more likely to do early merges and zipper merges together. Well, not the same person, but I may see it in the same area. The early mergers usually don't block traffic waiting for opening. It's usually that they see the gap in traffic and take it immediately.
People tend to stick to the outside lane as they feel that if they go on the inside lanes they won't have the opportunity to move to the outer lane when they are near their intended exit due to other cars being on the outer lane.
IMO this stems from lack of education (driving lessons are not adequate) and the fact that everyone's looking after themselves (i.e not respect for other road users (which also explains the ludicrous speeds on the roads, road rage, queues, etc))
(And don't get me started on driving lessons. Here, in the UK, they're an absolute joke!)
http://r-m-t.org.uk/wp-content/uploads/sites/5/2014/06/spiri...
This has caused me to shit a number of bricks in the UK, where two-lane roundabouts are a lot more common.
Jumping the queue counters this negative effect and is the correct behavior (in slow traffic).
In Germany, this behavior is explicitly forbidden by the law.
If there is a merge, one car of each lane has to go through the merge each time.
That is, if you are at the end of the lane that gets merged, and you let one car pass, then you have the right to go and merge next. The next car in the other lane must yield, if they don't and there is a crash, it's 100% their fault.
This is so that the lanes that merge get used to their maximum capacity. If the intent were for cars to merge earlier, they would just have made these lanes shorter.
Just like the ramp meters that limit cars entering the freeway. But instead a dual light that encourages zipper merging via offsetting green signals for each lane.
In a more general sense on a highway any time a car comes to a full stop you have the chance to create a phantom traffic jam as the stop travels back along the incoming stream of cars.
https://static1.squarespace.com/static/5005afd7e4b0a6953320b...
Not sure where all that anger comes from but I am happy that a hardly ever saw it in other countries where I drive or take a taxi.
What most Americans have a hard time understanding is that German driving school, or Fahrschule, requires the student to master these "advanced" techniques. Unlike in the USA where if you can operate the throttle and the brakes you're good to go.
As an English driver: <extreme tutting> get to the back of the queue like everyone else!
As a Cambodian driver: we are all stuck in a sea of motos, and being on time for anything is unimportant. Of course you may merge into my lane.
What that means is if someone tries to push their way in, I will block them off.
If someone is stuck and trying to get out of a side road / park, I will always let them in.
http://mynorthwest.com/474290/washington-traffic-law-reminde...
I certainly see it sometimes. I also see people preventing it sometimes by straddling both lanes.
Actually lane straddling doesn't even work to prevent someone from using the zipper rule. It prevents people from passing other people on the right (nobody should be passing anyone on the right most of the time anyway). But it doesn't prevent someone from merging into the other lane when the time comes. As long as you're pacing yourself vs. the speed of the traffic in the lane you want to merge into, everything's fine. Using the zipper rule doesn't mean you race ahead of everyone before merging, if anything it means waiting a little bit longer and maybe even merging behind a car you would otherwise be tempted to merge in front of.
When traffic is at its peak, it approaches its ideal state: the on-ramp is fully occupied with cars (no space wasted), and everyone's driving at basically the same constant speed up to the merge point, where everyone neatly and cleanly merges, alternating lanes. But if traffic is not at its peak, zippering doesn't require you to race ahead to merge point.
It wouldn't hurt anyone if you did that, of course. Same for everyone else waiting to merge. But there really are lots of people (where I drive at least) who are already on the road/freeway/whatever, who will move onto the (about to end) merging lane, race up to the end of it and force themselves back on the road, a few cars ahead. I've seen so many bad traffic jams made so much worse by people doing this. It makes a bad situation so much worse for everyone. Those are the people the straddlers are guarding against, not the well-mannered zipperers trying to do the right thing.
> But there really are lots of people (where I drive at least) who are already on the road/freeway/whatever, who will move onto the (about to end) merging lane, race up to the end of it and force themselves back on the road, a few cars ahead. … It makes a bad situation so much worse for everyone. Those are the people the straddlers are guarding against, not the well-mannered zipperers trying to do the right thing.
This is basically incorrect. Regardless of how you and straddlers feel about this, using up that empty merge lane on the right is more efficient than straddling or other forms of early merging. That's my understanding, anyway.
Pushing congestion backwards is exactly the cause of a lit of traffic jams. I've observed this myself every single GD day on the 210W freeway between Hill exit and the 134 exchange. People get over way early, causing huge congestion to the merge entrances. If they'd stay left and zipper, everyone in the jam would save about 5-10 minutes. This is thousands and thousands of dollars a day of cost in completely avoidable congestion in just one two mile stretch of highway ( albeit it a particularly egregious one)
In the ideal scenario of zipper merging there is no free right hand lane to shoot ahead in: it is completely filled with people that are alternately taking turns with the other lane to enter the merged lane. The queue is half the length in this case then the prior case. The lane straddler doesn't feel taken advantage of since everyone is entering the queue in the first available location (left or right).
Lane straddlers perform an illegal maneuver (I assume intentional driving in two lanes is illegal in most countries) to pre-empt the more efficient usage of the road. Their righteousness is unjustified: the person that would otherwise pass them in going to the front of the lane would be increasing the utility of the road. They would be more considerate by entering the lane they are blocking and going to the front themselves.
It all seems very theorical and not that useful.
And I see this working every day since where I live the rule applies. Of course there will always be the occasional smart guy who rides in the ass of the car in front in order to not let anyone pass and save 1-2 seconds at the price of causing everyone behind him 10 times the delay. This forces the cars trying to merge to come to a full stop, then forces some of the cars on the other lane to fully stop in order for the merging cars to be able to accelerate and merge.
A similar event comes to mind when you come across someone sitting in the left lane going under the speed limit but completely unaware or bother for the people passing them.
So I guess my point is, while these are great in theory, they don't really work in practice without buy in from the herd (I use herd as this problem can be framed in a similar light as vaccinations and herd immunity).
In the US, when you get to the end of the merge region, most people in the continuation lane will blast by at full speed, leaving no room to get over. I have to sit at the end of my lane, stopped, until I see a gap, and then floor it. That's worse for safety, fuel efficiency, wear and tear on my drivetrain, my own transportation time, and overall road throughput (everyone blocked behind me).
This is a "boil the oceans" type solution. All you have to do is convince everyone to do it.
Here, we can't even get people to stop blocking the box. The SPD is making short YouTube videos with "PRO TIPS" like "Bus lanes are for buses" [1] and "Don't stop in the street" [2]. The average driver is not at the point of thinking about higher level strategy like merge location yet.
[1]: https://www.youtube.com/watch?v=s_62iDA5Z-s [2]: https://www.youtube.com/watch?v=S3dUj6-Kx5k
I'm not talking about merging onto a freeway from an on-ramp. (I'm told the relevant law for on-ramp merging right-of-way varies by state, in the US.)
> The only time other vehicles should have to change their speed is in heavy traffic, when a gap might not exist.
Heavy traffic is the only time a zipper merge might be relevant in the first place, no? In light traffic, just get in the correct lane whenever you want. It doesn't affect anyone else no matter where you do it.
In fast heavy traffic (when drivers aren't leaving the requisite 4 seconds between cars), there's no reasonable gaps into which to merge. Signaling my intention doesn't change anyone else's behavior, and I don't have the guts to sneak my car into a 20' gap at 60mph. Even if I make it, if the driver in front taps the brakes even slightly, we're all going to have a real bad day.
This is a perfect example of how you can't just transplant one aspect of German driving, in isolation, to American highways. On the Autobahn, nobody's driving full speed for an extended length of time at only 1-1.5 car lengths behind the car in front of them. It's reasonable to say "just merge into the gap" because they leave a gap to merge into.
I don't understand what is being further proposed? Making it illegal to merge early?