
The utility of switching lanes when stuck in traffic - barretts
http://blogs.reuters.com/felix-salmon/2014/04/11/the-utility-of-switching-lanes/
======
panarky
Counterintuitively, in stop-and-go traffic everybody spends more time watching
others pass them than passing others.

Let's say you have to drive 100 km. Half of the distance your lane moves at
100 km/h, and the other half your lane creeps along at 10 km/h.

So you'll spend 50 / 100 + 50 / 10 = 5.5 hours in the car, at an average speed
of 18.18 km/h.

For every one minute you spend passing other cars, you'll spend 10 minutes
watching other cars whiz by you!

Even though the fast and slow distances are evenly distributed, all drivers
perceive that they're in the wrong lane.

~~~
ScottBurson
Excellent observation!

Sometimes I pick a car in the next lane to track and compare my progress with.
Although one of us will sometimes leave the other behind for a few minutes,
usually we return to rough parity eventually.

~~~
madcaptenor
Back when there were tollbooths where you had to pay cash, I remember seeing
aggressive lane-changers, tailgaters, etc. pass by and then seeing them
waiting in line, having gotten no further than us, at the toolbooth.

------
beloch
Switching lanes in dense traffic does reduce flow and increase everyone's
commute time. Cutting across a couple of lanes, exiting the road and then
merging back in a few blocks later is even worse. If more people thought of
driving as team-work rather than a race we'd all spend less time in traffic.
This fellow argues that behavior that slows traffic down is a good idea
because if makes him feel good. I'm sorry buddy, but you're an idiot. You're
taking actions that do not benefit you and harm me because you lack the mental
discipline to relax and stop treating traffic like a race.

Here is a suggestion for those of you who are currently like this guy but are
willing to try driving smart for a change: Don't alternate days. Get into one
lane and stay there and continue to do so for a couple of weeks. Listen to the
radio. Think about stuff you need to think about. Zen the #$%^ out. Once you
unlearn your moron-driver habits you'll arrive at your destination a lot less
stressed out and you'll have the peace of mind that you're not one of the
morons adding to the problem.

~~~
luckyno13
How about not going the route of "zen the #$%^ out." I prefer the drivers
around me to be aware of their surroundings and conscious of their driving,
not lost in dreamworld.

~~~
Xero
zen != daydreaming

~~~
logfromblammo
When I'm stuck in traffic, I consider that a time to submerge the ego, embrace
the virtue of patience, and realize that the goal of all drivers should be for
everyone to get everyone unstuck and return to normal traffic flow.

So rather than sit bumper-to-bumper, I will open a car-sized space ahead of
me, and intentionally allow "line jumper" cars to enter it. Rather than
alternately hitting the gas and brake, I'll just let my car roll, smoothing
out the wavelike interactions in congested traffic.

If you stop thinking purely of your own self-interest, you can act to improve
the overall flow of traffic, rather than just try to get yourself out of it as
soon as possible. Think of it as an engineering problem. Instead of how to get
1 person home as quickly as possible, try to get 10000 cars to their
destinations with the lowest median travel time, using only your ability to
control one car in the flow of traffic.

------
jamesbritt
What I dislike about traffic isn't the delay so much as the cognitive load. I
will often take a temporally longer route if it means I am not constantly
watching for lane-changers cutting in front of me and then suddenly braking.

~~~
mattgreenrocks
This is why driving is exhausting. There's always a few people who, evidently
lacking any real stimulation in their lives, feel the need to constantly
jockey for positions on the road, endangering everyone around them for a mere
ego trip. It seems like many of these drivers view their driving habits as
reflections on them as a person; e.g. they cannot appear weak by yielding to
others (even if yielding produces an optimal result, time-wise).

I can't wait for driverless cars. We are the ones who make traffic much worse
because we have to have our own way.

~~~
ipsin
There seems to be an implicit assumption that people who constantly jockey for
position and those who value safety and orderly progress will end up using
essentially the same driverless car OS.

Unless the field is heavily regulated, I imagine that car manufacturers are
going to tune and market their cars according to their existing brand
identities: safety, economy, performance, "thrill", and so forth.

It'd definitely be an improvement, but I also think it'll take decades to work
out the kinks.

~~~
kbenson
I think once we have good statistics on how different strategies affect
traffic and accidents, some states will fairly quickly respond with
requirements for how driverless cars must act based on that data.

------
dworin
Reminds me of this NYTimes article about queuing theory:
[http://www.nytimes.com/2012/08/19/opinion/sunday/why-
waiting...](http://www.nytimes.com/2012/08/19/opinion/sunday/why-waiting-in-
line-is-torture.html?pagewanted=all)

I tell this story all the time to help clients understand that customer
perception is more important than reality:

"SOME years ago, executives at a Houston airport faced a troubling customer-
relations issue. Passengers were lodging an inordinate number of complaints
about the long waits at baggage claim. In response, the executives increased
the number of baggage handlers working that shift. The plan worked: the
average wait fell to eight minutes, well within industry benchmarks. But the
complaints persisted.

Puzzled, the airport executives undertook a more careful, on-site analysis.
They found that it took passengers a minute to walk from their arrival gates
to baggage claim and seven more minutes to get their bags. Roughly 88 percent
of their time, in other words, was spent standing around waiting for their
bags.

So the airport decided on a new approach: instead of reducing wait times, it
moved the arrival gates away from the main terminal and routed bags to the
outermost carousel. Passengers now had to walk six times longer to get their
bags. Complaints dropped to near zero."

~~~
edgarvaldes
And reminds me of this: [http://davidmaister.com/articles/the-psychology-of-
waiting-l...](http://davidmaister.com/articles/the-psychology-of-waiting-
lines/)

"Sasser (et al) provide good examples of both managing the perception and the
expectation of waiting times. For the former, they offer the example of ‘the
well-known hotel group that received complaints from guests about excessive
waiting times for elevators. After an analysis of how elevator service might
be improved, it was suggested that mirrors be installed near where guests
waited for elevators. The natural tendency of people to check their personal
appearance substantially reduced complaints, although the actual wait for the
elevators was unchanged. "

~~~
logfromblammo
I once worked in a building that installed television sets near all elevators.
Unfortunately, those televisions were almost universally tuned to ESPN or Fox
News, when not simply turned off. I usually just took the stairs.

------
lutorm
Of course, the fact that switching lanes or not doesn't make a difference in
how fast you get to your destination does _not_ imply that _everyone_
switching lanes doesn't make it slower for _everyone_.

~~~
deeviant
It kinda does actually.

It speaks to the fact that perception of moving faster does not match reality.

~~~
3JPLW
Regardless of their perceptions or actual travel speeds, the lane-switchers
could be providing a much needed liquidity between the more dynamic right
lanes (with entrances and exits) and the more static left lanes. Perhaps it's
in doing so that they unwittingly ensure that everyone arrives at the same
time. (Although it's almost certainly not the optimal time…)

~~~
lutorm
I was thinking the opposite - lane switchers cause "turbulence" in the flow
and hence contribute to slowing everyone down.

~~~
slantyyz
I don't know how it is elsewhere, but in the Toronto, Canada area, driving
behaviours have gotten really bad over the past 20 years.

We have the worst kind of lane switchers. Here, they often jump into the short
lane on the right, which is reserved for cars entering and exiting the road,
to cheat back in. This is a real problem, because they slow down traffic even
more when they have to force their way back in.

~~~
logfromblammo
The counterintuitive solution to this is to always make room to let those
people back in. You aren't helping them "cheat", not really. You are keeping a
potentially dangerous driver in front of you, where you can more easily keep
an eye on them, and allowing them the opportunity to get the hell away from
your car.

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cjauvin
The philosopher Nick Bostrom has an interesting view about this question,
based on the selection effect[1]: if you consider your presence in the traffic
as a random sample from "observation acts", then you are more likely to be in
the wrong lane (and hence would benefit from switching), simply because it is
denser, i.e. it entails a higher probability mass for obversations of that
type.

[1] [http://plus.maths.org/content/cars-next-lane-really-do-go-
fa...](http://plus.maths.org/content/cars-next-lane-really-do-go-faster)

------
kpapke
What I do in crawling traffic is stay in 1st gear at a steady pace and stay in
the same lane to reduce the annoyance of starting & stopping so much. You'll
notice that large semi trucks do this too. It really benefits everyone if more
people did this.

~~~
rsl7
The hardest part about that is remaining sane as idiots cut in front and
undermine this strategy

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mhb
He should also test switching to the slower-looking lane in anticipation of
others switching to the faster-looking lane.

~~~
erobbins
I often find that by moving right I pass a TON of people who shifted left in
anticipation of heavy traffic ahead.. left lanes back up, right lanes open up.

~~~
Karellen
Also, I find that truck drivers have a preference for maintaining a consistent
low speed, rather than doing stop/start all the time. So I like to get in the
slow lane with them, switch to a low gear, and drive using only the
accelerator, losing imaginary good-driving points every time I have to touch
the brake. Slower or faster overall? Meh. It's a lot less work/stress, which
is a good trade as far as I'm concerned.

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robrenaud
> ... the act of changing lanes, and thereby briefly overtaking the car which
> up until a moment ago was in front of you, makes you significantly happier
> than just sitting there like a passive schmuck. Which is why we all do it.

> In other words, if you want to understand utility functions, don’t talk to
> an economist.

It seems like talking to an economist works pretty well here.

If I am executing a poor strategy that doesn't actually help me get my job
done any better, I shouldn't be happy about it. Especially if I know what I am
doing is ineffective.

If you know that the stay the lane strategy that you are executing is optimal
and that the lane switching doesn't help, then you should just stop being so
frustrated. The high intensity switching won't get you there faster. Accept
it, move on.

I liked my nexus 7 tablet a lot. One day I dropped it, the screen was smashed,
and it was useless. I was a tiny bit sad (essentially, I lost $200), but then
I just went an ordered another and moved on. Because I knew about the sunk
cost fallacy, I could just unemotionally do what was optimal.

~~~
pavelrub
You don't get it. The whole point is that the average person is willing to
switch the time he might gain from not switching lanes with the happiness he
gains from the appearance of progression. The "goal" of saving time on the way
to work/home/other has value because people choose to give it value, and when
they don't - it becomes meaningless.

~~~
robrenaud
I do get it. The people are irrationally pleased by the illusion of progress.
Upon learning that their strategy is ineffective, executing the broken
strategy should bring them no utility.

~~~
pavelrub
No, you obviously don't. The notion of "effectiveness" exists only when there
is an agreement on the goal. If my goal is to have fun while driving - then I
don't care about the type of "effectiveness" you have in mind, nor should I.
And there isn't a single thing you can say to convince me that saving 5
minutes during commute is objectively more important than having fun while
driving. This is also why we usually walk from place to place instead of
running: walking is slower, but running and getting tired is not very fun: and
most people choose fun over speed. People are not computer software, and
what's important to us is not defined by god.

This is also why utilitarianism in ethics is ridiculous.

------
rojoca
> This is important: the really painful part of being stuck in traffic is not,
> really, the actual amount of time that it takes to get from Point A to Point
> B. Rather, it’s the “stuck” bit.

I've noticed this tends to not matter so much if you're not the one driving,
more so if you're in the backseat. Self-drive cars anyone?

~~~
npizzolato
Or the lower technology version that's available today: public transportation.

~~~
sirmarksalot
The stress of commuting isn't from the physical act of driving, but from
having to negotiate a crowded space. Regardless if it's a highway, bus, or a
sidewalk, when you're in a crowd, you're forced to play a zero-sum game with
the people around you. Even in cultures where people don't drive, the commute
is listed as one of the largest stresses people experience.

Self-driving cars are great because for the first time, you have a machine
that commutes for you. There's no competition to get in the car, no
competition to sit down in the car, and once the car starts moving, you don't
have to care about how the car navigates the competition on the road.

It's true that on the large scale, it's less efficient than public
transportation, but on an individual level, it's the best option.

~~~
npizzolato
>The stress of commuting isn't from the physical act of driving, but from
having to negotiate a crowded space. Regardless if it's a highway, bus, or a
sidewalk, when you're in a crowd, you're forced to play a zero-sum game with
the people around you.

I disagree. The stress from driving doesn't come just from navigating a
crowded space. It comes from the potential consequences of making mistakes. If
I bump into someone walking on foot, it's no problem. Once I'm on a
bus/train/etc. you have your own space. Granted, it might not be a lot of
space, and sometimes it might be uncomfortable, but it's hardly stressful.

Bumping into another car when driving is a completely different beast. Now I
need to deal with insurance companies, and it might cost me a lot of money. Or
I hit something inanimate and I'm still doing a lot of damage to my car.
That's where the stress comes from.

------
muaddirac
Related observation: I have an hour/hour-and-half commute, and I've noticed in
particular that it doesn't pay off in any noticeable way to speed (~10-15
over) on the interstate. At best you shave off a few minutes, but those saved
minutes can easily be eaten back up by traffic and traffic lights in the non-
interstate parts of the commute.

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stronglikedan
I will only switch lanes when I can see what is causing the blockage. If it's
an accident to one side, I get to the other. This avoids the mess of merging
at the last minute.

Having tested this by noting the positions of large distinct trucks that I can
see form a distance, I've noticed that I do get through the jam faster this
way.

------
ChuckMcM
At one point I tried to do something like this on my commute (before I
switched to using the train). I wrote a simple Android App which would plot
time and position during the entire commute and I'd decorate it with 'all lane
#1', 'all lane #2', etc. The idea was to plot the 'currents' which is to say
which lanes were faster at which points of the commute. Needless to say there
is a huge time dependency. There is also a 'kids' correlation where non-school
days are faster than school days (which I found interesting). The train takes
a bit longer (less than worse case driving, a bit longer than the median
driving time) but being able to read totally makes up for that.

------
cafard
We have arguments in the car from time to time, for we live just north of a
half-mile stretch of road that is is congested for most of the daylight hours.
My argument is that switching to the street a couple of blocks over produces
the illusion of progress, but no real gain. Sticking to the nearer road is
obviously stop and go, but lacks a couple of bottlenecks further down, and is
thereafter faster.

I'm not sure whether my reasoning convinces my wife, or she just finds the
left-hand turns inconvenient.

------
snowwrestler
Changing lanes makes sense when there is a substantive reason to do so. The
other lane moving faster is not substantive; it's observation. If you have no
idea why it's moving faster, you have no idea whether switching will help.

But if you drive the same route every day, it is possible to find inflection
points in the traffic patterns, where you want to go one way and a significant
portion of the traffic wants to go another. Optimizing around these points is
a good reason to change lanes.

------
JoeAltmaier
Switching lanes doesn't make me happy. Accepting the situation makes me happy.
Angling for a few seconds benefit, dodging other anxious drivers etc makes me
surly and unhappy.

------
omerhj
Paul Krugman blogged about this subject last year:

[http://krugman.blogs.nytimes.com/2013/07/26/friday-night-
mus...](http://krugman.blogs.nytimes.com/2013/07/26/friday-night-music-sprawl-
again/)

with a followup here:

[http://krugman.blogs.nytimes.com/2013/07/28/life-in-the-
slow...](http://krugman.blogs.nytimes.com/2013/07/28/life-in-the-slow-lane-
trivial/)

------
drcube
It's not about getting anywhere faster. It's about not being trapped, and
about having control of my own situation. Hell, I'll drive 12 hours rather
than spend 6-8 dealing with airport bullshit, for precisely that reason. I
want to be in control, and I don't want to be trapped.

------
ape4
Cliché, I know: you aren't stuck in traffic; you are traffic.

