
The Zipper Rule on German Roads - mpweiher
https://www.ozy.com/immodest-proposal/german-roads-are-smarter-than-yours/60839
======
danieldk
This is not really specific to Germany. Zipping is also used in e.g. in The
Netherlands and Belgium. It's been required by law in Belgium since 2014 and
has been campaigned in The Netherlands since 1989 (apparently).

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.

~~~
Cthulhu_
In my experience, zipping as described here - when getting onto the highway -
isn't done properly in NL. People still try and force themselves onto the
highway or other lane as soon as possible. My colleague called it "eerste
blokjesangst".

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.

~~~
nf05papsjfVbc
Usually, it is safer to merge behind the truck.

~~~
davedx
Not sure about that. Trucks generally have very powerful brakes and can stop
faster than you'd expect. Crashing into the back of a truck can be
catastrophic.

~~~
UI_at_80x24
I'm a Part-time truck driver.

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...](https://www.hg.org/legal-articles/stopping-distances-for-commercial-
vehicles-28265)

------
sowbug
Tom Vanderbilt's _Traffic: Why We Drive the Way We Do (and What It Says About
Us)_ contains the same conclusion that late merging leads to less congestion
because of fuller utilization of available lanes. Related reasoning supports
the London Underground's Holborn Station experiment to encourage escalator
users to stand on both sides, rather than the customary stand-to-the-right,
walk-to-the-left.

[https://www.amazon.com/dp/0307277194](https://www.amazon.com/dp/0307277194)

[https://www.nytimes.com/2016/06/13/world/europe/a-london-
sub...](https://www.nytimes.com/2016/06/13/world/europe/a-london-subway-
experiment-please-dont-walk-up-the-escalator.html)

~~~
astrodust
The stand right, walk left tradition here usually works well, and it's not
like the left is empty for a lack of walkers.

Maybe it's cultural or depends on how eager to walk people are as to
utilization factors.

~~~
dbaupp
Standing is denser than walking, so the throughput is greater (at the cost of
latency, for those who would walk). I believe the station only encouraged the
break in tradition at peak times, when there are significant numbers of people
waiting to get on.

~~~
jrbancel
> Standing is denser than walking, so the throughput is greater

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.

~~~
frosted-flakes
Holborn's escalators are over 23 metres tall, as tall as a six or seven storey
building. Very few people will walk up the entire escalator, essentially
limiting utilisation to 50%.

------
henrikschroder
Sweden has the same laws, but everyone still merges early because some sense
of "fairness" kicks in, and people don't understand that they're making any
queuing worse by not utilizing all available road surfaces.

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.

~~~
Angostura
As a Brit, I always merge early due to the sense of fairness. However, this is
strongly enforced by the nature of road signs, which show, say 500m ahead, a
diagram with an arrow on the right merging to the left.

All it would take would be a consistent change of sign showing merging in turn
at lane-merge to change this behaviour

~~~
lorenzhs
This is the sign for a zipper merge in Germany:
[https://www.swr.de/-/id=22217882/property=gallery/pubVersion...](https://www.swr.de/-/id=22217882/property=gallery/pubVersion=1/d6vtby/r.jpg)
(the text says "zipper merge, no sooner than in 400m"). But we also have the
arrow sign you describe, albeit with the same text as the other one:
[http://www.steine-und-erden.net/se501/reissver.gif](http://www.steine-und-
erden.net/se501/reissver.gif). It would be interesting to conduct a study on
whether there is a change in behaviour depending on which sign is used.

~~~
Angostura
That would be perfect.

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.

------
numlock86
This sounds good in theory, but it works less than one out of four times. (no
negativity bias included) There's always someone not following the rules,
which in human nature automatically grants every observer to do the same.
Following local news right now it seems people aren't even capable of
"Rettungsgasse" (leaving a corridor for emergency vehicle access in traffic
jams) anymore, a concept also encoded in law here. Sincerely, a German who's
on the Autobahn on almost daily basis.

~~~
baxtr
Strange. I see it working in practice 80% of the time... I’m on the road a
lot, too. “Rettungsgasse” is something that regained popularity in the last
years due to strong media push.

~~~
CalRobert
For what it's worth, foreigners driving there may not be aware of the rule. I
tried as hard as I could to be a conscientous, informed road user before my
first trip to Europe (studied signs, rules of the road, etc.) but still got an
angry motorcycle cop whacking my mirror in France because I thought emergency
vehicles would pass on the shoulder and had moved over to allow this, not in
this Rettungsgasse (or the French equivalent)

~~~
danieldk
What makes it worse is that the rules differ, even in EU countries. In Germany
you have to make a 'Rettungsgasse' when there is a traffic jam, whereas e.g.
in The Netherlands, emergency services use the 'vluchtstrook' (outermost lanes
not used for traffic) in such cases.

~~~
davedx
Except where they've decided to let regular traffic use the vluchtstrook to
drive on. Some roads you just need to be aware that you might need to make
room for an emergency vehicle coming between the lanes.

------
wil421
I’ve heard of the zipper merge in the US too, many cities and states recommend
it. I much prefer the zipper merge and I’ve always done it before I knew the
name. Some states are even putting up signs about it.

Minnesota[1]. Other states[2]. My home town[3].

[1][https://www.dot.state.mn.us/zippermerge/](https://www.dot.state.mn.us/zippermerge/)

[2][https://www.fleetowner.com/driver-management-resource-
center...](https://www.fleetowner.com/driver-management-resource-center/magic-
and-mystery-zipper-merge)

[3][https://www.ajc.com/news/local/gridlock-guy-
transportation-o...](https://www.ajc.com/news/local/gridlock-guy-
transportation-officials-urge-use-zipper-merge/BaKOEqwrhAD0597B5fSssM/)

~~~
NickBusey
This has seemed so obvious to me forever, but I remember two instances very
clearly that illustrate how much people generally hate it in the US.

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.

------
Gasp0de
I get why zipping vs. early merging causes shorter traffic jams, but I don't
get why it would be more efficient in terms of speed. If 50 cars can pass the
bottleneck per minute, 1000 cars will always take 20 minutes, no matter if
they cue in one or two lanes? Wether a jam is 1 or 2km in length only matters
if there is an exit blocked by it, right?

~~~
Cthulhu_
The problem with early merges is that there's no way people that merge in are
at highway speeds when they merge, causing everyone behind them to have to
slow down, which eventually can cause traffic jams. Just use the whole lane,
make SURE you're going the same speed as the rest of traffic. The confusion
there is that because of an existing jam or slowdown, people are already at a
matching speed at the start of the on ramp. Or so they think.

~~~
dsfyu404ed
>The problem with early merges is that there's no way people that merge in are
at highway speeds

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.

------
EricE
I can't believe this is even debatable. Near my house there are a couple of
lights where the road opens up to two lanes before the light, then after the
light narrows back down to one lane.

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 :/

~~~
mhdhn
Maybe they feel the right lane is only for people turning right?

~~~
seattle_spring
Then it would be a right turn only lane...

~~~
pnutjam
Yes, we have roundabouts where this happens. I also see this at the interstate
on-ramp by my office.

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.

------
IshKebab
In the UK I had someone almost try to crash into me when continued along a
totally empty lane 200 yards before the merge point, while everyone else was
queueing in one lane.

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](https://imgur.com/a/rCw4vJ7)

~~~
gvurrdon
Based on your description of the scenario I'd think the driver in question
considered you a "queue jumper", and their fury at what they perceived as your
objectionable driving would cause them to act unsafely.

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.

------
bauc
It's funny that the article states it doesn't happen in the UK, but according
to the highway code you are are supposed to. Many people seem disagree with
that and like to queue but should read their highway code
[https://www.rac.co.uk/drive/advice/driving-advice/zip-
mergin...](https://www.rac.co.uk/drive/advice/driving-advice/zip-merging/)

~~~
ChrisRR
That's what I was confused about. The article says we don't do it in the UK
but then describes what we call "merge in turn"

~~~
bauc
Yes, but I can believe people not seeing it being applied. A lot of people
don't like it for whatever reason. Only ignoring it seems to create (or
worsen) the problem in the first place

~~~
tomatocracy
At least on motorways, this is because more often than not you will be going
too fast to do this safely by the time you run out of lane. Most drivers will
be conditioned by that experience to expect it unless they can see evidence to
the contrary. This is also why the signs indicating lane closures will usually
be half a mile or more before the actual closure. When the traffic is slow
moving to start with people do tend to merge in turn.

------
jimhefferon
Where I live there is a very strong culture of politeness and kindness in
driving. For instance, I often see (and do it myself) that someone has let a
person in who is trying to pull out of a hard-to-leave business driveway, with
no hope of reward, just out of a sense that other people have helped you out
in the past so now it is your turn.

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?

~~~
nmeofthestate
Same here (Scotland). I think the tendency to queue and not fill both lanes is
out of a misplaced sense of fairness - you can't help but feel very judged if
you run right up an empty right-hand lane all the way to a merge point.
Because you really are queue jumping, even if it's the collective fault of all
the drivers who created the queue in the first place.

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.

~~~
alkonaut
Norms change slowly and queueing is a strong social norm. But if it's actually
tought in driving schools or even made into law then we can usually overcome
it.

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.

------
gorpy7
In many cases the lanes weren’t designed for zipper merging or drivers “zipper
merge” at inappropriate places. Zipper merge is great! But not all merging is
to be a zipper merge- this is constantly abused, and perhaps justified in the
minds of offenders under the guise of the zip. A lane, such as an entrance
lane, that terminates is a good time to zipper merge. But many many times, in
Minnesota, people use any lane that allows them to cut to the front of the
line. Regardless if that causes a massive slowdown as they leave the
relatively free flowing lane and “zipper merge” - match speed of the slow
lane. Articles would do well to mention the finer points before ushering us to
10% gains... maybe.

~~~
jmkd
Glad to see lane design mentioned, it's a key component. In most zipper merge
opportunities there is a predominant lane and another lane that is ending,
leading to the idea of a 'right' and a 'wrong' lane which precludes intuitive
zipper merging. If lane design (even just the markings) were such that both
lanes were equal prior to the merge, zipping together would seem the most
natural thing to do whether signposted or not.

------
seniorsassycat
If the culture is early merge and you choose to late merge you will be
skipping the line and people will resent you for it.

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.

------
tssva
A US driver and it may not be the law but the zipper move is certainly the
norm in my area.

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.

~~~
noxToken
I've also had the pleasure of driving in multiple states. The zipper merges
seems to be true everywhere that I've been. Even the purportedly terrible
Orange County and LA drivers user zipper merging.

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.

~~~
bagacrap
Southern California drivers certainly aren't terrible, and if that's a
reputation they carry among outsiders it's probably because they're more
aggressive (efficient) and leave less space than those from parts of the
country where real traffic doesn't exist.

~~~
noxToken
They absolutely aren't terrible. I do think some SoCal drivers can be a little
over aggressive to the point where it is unsafe, and this tends happens with
multiple lane changes to make an exit. No matter where you go, you'll have
adrenaline junkies in coupes and on bikes weaving around cars, distracted
drivers, rubberneckers, and fender-benders that refuse to move to the
shoulder.

------
alkonaut
I'm living temporarily in spain and notice something similar: they basically
don't use the inner lane in roundabouts. So people go 3/4 of a lap on the
outside lane which can be clogged while the inside is empty.

~~~
dark_ph0enix
Exactly the same problem in Portugal.

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))

~~~
oneeyedpigeon
I hate roundabouts, at least partly for this reason. Whenever I'm taking
anything other than the first exit, I'm moving round just praying that no-
one's going to join or drive up alongside me...

(And don't get me started on driving lessons. Here, in the UK, they're an
absolute joke!)

------
captainpete
Kiwis have this rule, signs saying "Take this tip: merge like a zip!" (think
of it said in a happy kiwi accent). Driving in Australia without the rule,
merging gets personal quickly.

------
ivanhoe
This rule exists in many European countries, but afaik it only applies to
situations when the lane is blocked or stops there, so all cars have to move
into one lane. It's totally OK however to not let into the lane people who're
using an empty lane on purpose to pass by others and jump the queue. If the
car has the road in front of it to continue moving, so they don't need to
switch the lanes, you don't have to let them in.

~~~
floofy222
> t's totally OK however to not let into the lane people who're using an empty
> lane on purpose to pass by others and jump the queue

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.

~~~
ivanhoe
Absolutely, but only if there's a merge of lanes. If this is just the empty
lane that people use to get to the front of the queue, like when there's a
traffic jam to enter the highway and some cars are trying to cut the line,
then you don't have to let them. I'm aware that this is not a common problem
in normal countries like Germany where drivers generally behave well, but if
you ever find yourself waiting in a line somewhere in Italy or say in Balkans,
you'll often see cars trying to push past you by cutting the queue using empty
and service lanes.

------
gregopet
It's not just drivers who don't let someone from the empty lane 'cut in' \-
there are those that stop completely and let in 3 or 4 'poor sods who were
stuck on the wrong lane'. This breaks the system just as badly! The trick is
to merge 1-1 as fluently as possible or you've broken everything.

------
mark-r
I see a lot of talk of fairness to justify the urge to merge early. This is
ironic since zipper merge is the fairest of all, if you can only get everybody
to adhere to it. Nobody can get ahead if both lanes are full and moving at the
same speed.

------
pkamb
To encourage this behavior, why not put a stoplight in the middle of the road
at the merge point?

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.

~~~
rtkwe
A full stoplight requires a full stop which defeats a lot of the benefits of a
proper zipper merge where traffic just keeps flowing with no stops.

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...](https://static1.squarespace.com/static/5005afd7e4b0a6953320bf3f/t/57c6ceb69de4bb8747981006/1472646990392/?format=750w)

~~~
pkamb
[YIELD || GREEN] alternating lights then

~~~
zaarn
There is no Yellow-Green traffic light in germany. There is only Red, Red-
Green, Red-Yellow and Red-Yellow-Green.

~~~
pkamb
I'm speaking more about hypothetical new lights in the USA, Germany, or
elsewhere in the world.

------
tluyben2
I can see the comment in the post about the UK; I am used to this practice in
a lot of EU countries I go; in the UK however, they don’t do this and the
amount of roadrage there is quite staggering. I do not drive there but when I
am in taxis/Ubers, the amount of honking, cutting in, swearing, (racial)
insults and flipping the bird I have not seen in other countries. Ofcourse
mostly in/around large cities but I have seen it in tiny villages too; enough
anyway for me (YMMV) to think it is not an anomaly.

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.

~~~
jacquesm
Try driving in Bucharest or Athens for a bit and the UK will seem positively
polite.

~~~
tluyben2
I drove in Bucharest a few months ago; I did not notice this. But might well
be as this is all anecdotal anyway; I have been in the UK many times, I have
been in Bucharest once (I did not like it compared to other cities in RO).

------
shiven
Once self driving vehicles are the norm, such rules would become default.

------
6nf
New Zealand has some 'Merge like a zip' signs. I've not seen them in Australia
but people do know the rule. They just don't follow it all the time.

------
chkaloon
I've never actually seen this work in practice, so maybe i'm missing
something: Isn't the overall flow of traffic defined by the speed of traffic
within the narrow section? E.g. if the speed limit and actual speed of traffic
in the one- lane construction zone is 45mph, how people merge prior to that
point should be irrelevant. The same number of cars are going to get through
at the same rate.

~~~
pintxo
From my experience, the speed is most often lower at the merging zone then in
the following stretch of road. So overall througput could be improved by a
more strict merging regime.

------
User23
I independently rediscovered this driving in Southern California. It's the
obvious fair and efficient solution for two lanes merging.

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.

------
marcus_holmes
As an Australian driver: hahahahhahahhahahah you got Buckley's, mate. No f ___
ing way am I letting you in. Get f ___ ed

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.

~~~
lysp
As an Australian driver I like to use what I call the "Robin Hood Rule" \-
steal from the rich, give to the poor.

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.

~~~
leetcrew
I think this is a dangerous approach, as the more aggressive drivers are more
willing to play chicken and risk a collision. of course I follow the same rule
myself.

------
will_brown
I personally have never seen more efficiency on the road than Manila. Merging
is just on an entirely different level in the Philippines. I would recommend
going of course (not just to observe their driving) but there is no shortage
of YouTube videos of traffic/Driving in Manila.

~~~
FabHK
Or other countries in SEA, for that matter. The way to cross the road, as a
pedestrian, in Cambodia is this: Close your eyes and, with one hand raised,
walk across the road at a steady speed. Traffic will flow smoothly around you.
Any attempt to avoid traffic by walking faster/slower will confuse everyone
and lead to accidents.

------
toastermoster
I've always thought this would be best. I recently saw signs instructing
people to wait to merge in Duluth MN when I was visiting for work. People
weren't abiding by the signs though and continued to behave in the normal
random way they typically do when merging.

------
loeg
This is also the rule in the US, isn't it? Maybe just Washington?

[http://mynorthwest.com/474290/washington-traffic-law-
reminde...](http://mynorthwest.com/474290/washington-traffic-law-reminders/)

~~~
banana_giraffe
The article mentions Washington and Minnesota (and other unspecified states)
are trying to encourage it.

I certainly see it sometimes. I also see people preventing it sometimes by
straddling both lanes.

~~~
mwfunk
Lane straddling doesn't prevent people merging via the zipper rule. Rather, it
prevents people already on the road from moving over to the merging lane,
shooting ahead of a bunch of people, then merging again (slowing down everyone
else by adding to the merging traffic). It's one of those behaviors where
whatever convenience that person gets is greatly outweighed by the cumulative
cost to everyone else.

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.

~~~
mwfunk
I'm not normally one to complain about downvotes but I literally cannot
imagine how any of what I wrote was remotely controversial. Like I'm trying to
look at it with different interpretations and perspectives and I'm just not
seeing it. I've seen hotter takes in DMV driving guides. I'd be very curious
what the disagreeing opinions are and why. For the record, I've never
straddled lanes, I was just explaining why people do it.

~~~
BlackFly
In the ideal scenario of lane straddlers, everyone trying to enter a
particular lane at a particular point has to do so at the end of the line of
people already waiting to enter. The right hand lane is completely unused and
therefore the length of the line is double what it needs to be, possibly so
long that it interferes with other intersections.

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.

------
sureaboutthis
Somewhat related, I wish people would learn that, when turning right or left
onto a two or more lane road, you are to turn into the lane nearest you and
never the far lane. This way, a car facing you can turn onto the same road at
the same time.

------
arjunvpaul
For people who prefer videos -
[https://www.youtube.com/watch?v=cX0I8OdK7Tk](https://www.youtube.com/watch?v=cX0I8OdK7Tk)

~~~
sametmax
I don't get it: why not just put all the cars on one lane then ?

~~~
skocznymroczny
In a case of a highway it might not be as beneficial, but imagine a city with
lots of road intersections. If you put cars on two lanes and merge, you have
half as long line of cars. In case of one lane scenario, the cars might block
the previous intersection for other cars.

~~~
sametmax
In a city, you won't have this problems, as traffic will jam at the first road
work it encounter anway. Besides, how do ones plan to make all those people
collaborate ?

It all seems very theorical and not that useful.

~~~
close04
The drivers should know to leave just enough space in front of them for the
car on the other lane to merge. Having to stop for a merge makes everything
slower. It takes longer to accelerate so longer to clear the jam. Ideally one
lane slows down and leaves some spaces between the cars, and the other one
merges 1 to 1 without anyone ever having to brake to a full stop.

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.

------
FTA
I try to follow the zipper rule when getting on the freeway. The problem I run
into quite often in CA (and the thing that frustrates me the most in urban
driving) is when people behind me on a highway on-ramp cut across the solid
white line to "get ahead". That then forces me to have to slow down while they
pass so I don't ram them from the side. If you factor in other through-way
cars already in the lane, this can really congest merging and you get major
backups in the rightmost lane.

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).

~~~
ken
Yes, this is one of those concepts which works much better for everyone, _if_
everyone else drives like a German driver.

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](https://www.youtube.com/watch?v=s_62iDA5Z-s)
[2]:
[https://www.youtube.com/watch?v=S3dUj6-Kx5k](https://www.youtube.com/watch?v=S3dUj6-Kx5k)

~~~
frosted-flakes
Merging onto a freeway from an on-ramp is different, and zipper merge doesn't
usually apply. There's a reason the merge zone is 300-500 metres long (where
space permits), and depending on the region, clearly marked with a dashed
line. It's up to you to match the speed of traffic, then signal your intention
to merge before merging into a gap in traffic. Some on-ramps even have
metering lights to space out incoming vehicles to make this process smooth.
The only time other vehicles should have to change their speed is in heavy
traffic, when a gap might not exist.

~~~
ken
> Merging onto a freeway from an on-ramp is different, and zipper merge
> doesn't usually apply.

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.

------
Zardoz84
I never listen that this is a law here (Spain) or mandatory. But is what
usually people done here.

------
ojbyrne
Excellent book that mentions this as well as other counterintuitive facts
about driving: [https://www.amazon.com/Traffic-Drive-What-Says-
About/dp/0307...](https://www.amazon.com/Traffic-Drive-What-Says-
About/dp/0307264785/ref=asc_df_0307264785_nodl/)

------
ykevinator
It's sort of a nice thing that people choose nice over efficient.

~~~
seattle_spring
No it's not, and often being "nice" instead of doing the correct and
predictable thing while driving is extremely dangerous.

------
scurvy
Or just ride a motorcycle and do whatever you want wherever you want whenever
you want. ;)

------
grabbag
We do this in the US in many places. The difference is we don't need a law for
every common sense rule. And for some road configurations, strict adherence to
the rule wouldn't make sense.

~~~
aquabeagle
Alternating merging yes, but many people probably don't wait until the last
possible opportunity to do so. Some merge as soon as they can and think late-
mergers are trying to cut ahead.

~~~
mrep
That's because a lot of people like me don't/didn't know about the zipper
merge and asscoiate it with 1 lane exits where assholes try and merge into the
backed up exit lane after flying by everyone else in the other non queued
lanes and thus blocking other lanes.

~~~
mark-r
There's no worse feeling than realizing the backed up traffic in the right
lane that you've been buzzing by was waiting for the same exit you need. I
hate being "that guy" but sometimes ignorance catches you unaware.

~~~
mrep
Totally, that's why I let people in at the start of the queue and get more
aggressive about not letting in people the further I get into the exit lane
queue. I still let in people but the further into the queue I get, the less
permissive I am because if you fucked up, then accept the fact that you will
have to miss your exit and reroute back to your destination and hopefully you
won't be that asshole next time and enter the queue early.

