
Building Bigger Roads Makes Traffic Worse - data_scientist
http://www.wired.com/2014/06/wuwt-traffic-induced-demand
======
cs702
In addition to the correlation found by these researchers, I suspect the
Braess Paradox[1] and other complex network phenomena are also at work.

\--

[1] Adding more roads to a network of roads can make traffic worse (and
viceversa, closing roads can make traffic better). See
[http://en.wikipedia.org/wiki/Braess's_paradox](http://en.wikipedia.org/wiki/Braess's_paradox)
or watch this friendly explanation:
[http://www.youtube.com/watch?v=ZiauQXIKs3U](http://www.youtube.com/watch?v=ZiauQXIKs3U)

\--

Edits: moved links and parenthesis to footnote, and added "In addition to the
correlation found by these researchers" and "other complex network phenomena"
to make my point clearer.

~~~
bigdubs
The video doesn't do a good job of explaining this at all.

Ultimately the reason why adding more roads to a system produces more traffic
is more people take cars vs. public transit.

~~~
Spooky23
No, its much more complex than that.

Adding road capacity makes other types of trips possible. It's not a simple
"hey, I'm taking the bus today because they built a lane". It's more like
"Hey, I don't need to worry about uprooting my family or spending 6 hours on
the bus to get a job in place X vs Y."

Think about it in computer networking terms. Netflix and Office 365 didn't
exist in 1995 because it wasn't possible to make those sorts of solutions work
then. Today, we need to worry about network congestion because millions of
people are streaming movies.

~~~
ams6110
Very much so. New and bigger roads cause all kinds of associated growth. New
businesses and home pop up because it's now practical to get to them in those
locations. This increases demand for the roads, so they eventually become
congested again. But not just because people like to go from place to place
for no reason other than to go.

~~~
fleitz
It would seem then one way to spur economic growth would be to build more
roads, transit, etc. Just as building faster internet spurs more internet
companies.

~~~
Spooky23
Been there, done that... it's called 1946-2006.

------
nawitus
>This means raising the price of driving on a road when demand is high. During
rush hour, drivers would have to pay a fee to use the most congested roads.

Drivers already pay for the cost in lost time. It's a 'natural' market.

The main problem with this article is the idea that the goal in traffic policy
is to reduce congenstion. No, it should be to maximize utility. Sure, if you
reduce roads, add congenstion charges then people will find alternatives to
cars. That doesn't imply that utility is increased.

Public transportation is typically worse than using a private car. You can't
decide when to leave, you pretty much need to plan your trips around public
transportation. They don't take you directly from A to B etc. Public
transportation becomes effective only when population density becomes high
enough.

~~~
rayiner
But that's highly inefficient. Everyone pays in the form of time, but some
peoples' time is more valuable. Congestion pricing fixes that.

~~~
Avshalom
Well except that the people paid the least per hour are also the ones who can
afford to lose time the least and have the least ability to pay for
congestion.

~~~
Dylan16807
So the people who can least afford to lose time will avoid congested traffic
and lose less time? Sounds like that could work out well.

~~~
frandroid
If you wait an extra hour before commuting home because of the cost, I don't
call that "lose less time".

------
baddox
It's an interesting effect, and fairly obvious once you hear the explanation
the first time. This article focuses primarily on the effect that roads have
on their own congestion, but I think you can do similar analysis on the
effects of roads on many other things.

This sort of idea is discussed a lot in the libertarian community. I don't
intend to make the conversation about that; I just want to mention the ideas
because they're similar. Basically, a common and oft-parodied criticism of
libertarianism is "but who will build the roads," implying that massive road
infrastructure is something that can only be produced by government through
taxation and eminent domain.

One common retort by libertarians is to come up with a bunch of proposals for
how private enterprise could create a very similar road system to what we have
today. I think that's the wrong approach. I'm more interested in the ways that
government roads, no matter how well-intended they are, can lead to
inefficiency and perverse incentives.

I think the biggest and easiest argument to make is an environmental one,
which is somewhat ironic, considering that libertarians are generally
considered (by themselves and others) as a threat to environmentalism. And
yet, I wager that public road infrastructure is one of the most obvious cases
where government programs lead to (probably unintended) environmental
problems. The interstate highway system is a massive blow to railroads, which
have a vastly smaller environmental impact than road freight. The public road
funds essentially subsidize the price of fast shipping via truck. Big trucks
are probably responsible for a disproportionately large portion of road wear
relative to the funding of roads that they provide.

Another interesting effect is that urban sprawl probably wouldn't happen
without roads which are primarily produced by government. This is probably
another big threat to the environment, since I would imagine that suburbs
pollute much more per capita than urban areas because of the necessity to use
automobiles.

~~~
JPKab
The Chesapeake Bay-Bridge Tunnel is one of the largest bridge-tunnels in
existence. It's 17.6 miles long, and was financed by toll-backed bonds, and
continues to be maintained with toll money. The point being that large
infrastructure projects can be financed by the free market, provided they
require the users to pay for them in the future, allowing investors to profit.

Here in the DC region, demand-based pricing was used in the widening of
interstate 495. It works. My favorite aspect is that buses and vehicles
carrying 3 or more people can use the lanes for free, while all the assholes
riding by themselves have to pay handsomely for the privilege of creating
congestion at rush hour.
[http://en.wikipedia.org/wiki/Virginia_HOT_lanes](http://en.wikipedia.org/wiki/Virginia_HOT_lanes)

One of the funny things about the libertarian idea of making everyone pay for
road use is that technology has made it much more feasible. We don't have to
use toll booths anymore. Instead just stick a transponder on the window. One
of the best remedies for situations in which overuse of a public good is
causing environmental problems is to make people pay to use said good.

~~~
snowwrestler
Everyone paying for road use is not a libertarian idea. It's the basis of the
gas tax, for instance, which funded the Eisenhower interstate system--not
usually held up by libertarians as their ideal.

Likewise the Chesapeake bridge-tunnel was built by a government organization
funded by municipal bonds. Bond funding does not imply private ownership and
is not really a libertarian idea.

The 495 HOT lanes were a public/private partnership, so again not exactly a
libertarian ideal. Also, to date they are underperforming financially.

The best example of a libertarian-type road project in the DC area is probably
the Dulles Greenway, which was built and is operated by an entirely private
company.

------
tptacek
There was more or less a whole EconTalk episode about this recently; one
interesting point from it was the (bad) concept of STROADs:

[http://www.strongtowns.org/journal/2013/3/4/the-
stroad.html#...](http://www.strongtowns.org/journal/2013/3/4/the-
stroad.html#.U7GEXI1dUWs)

~~~
jessaustin
Thanks for this; it's a valuable concept I couldn't have articulated before.
It seems I see stroads _everywhere_ , and they do suck for pedestrians,
cyclists, shoppers, businesses, and humans, but there isn't an obvious way to
get from here to the improved future. At a certain population density, land
simply _is_ less valuable, no matter the road organization. I can imagine a
town trying (and enforcing!) the street concept in a couple-block area, but
how effective can that area be when everyone drives to get there? I almost
suspect we'd need regular bus service, but at low population densities how
does that work?

~~~
digikata
Use automated vehicles to supply an on-demand middle tier of transit. That
layer could possibly provide transportation bridging low-density regions to a
higher capacity fixed public transit nodes.

------
adamgravitis
Having done some grad work in this area, I'd say this is a fairly superficial
take on the topic. This certainly describes _one_ area on the supply/demand
curve, and perhaps even a pervasive one given that we essentially stopped
building highways 40 years ago, but it's not inherent to the problem.

I think it's very possible to jump ahead of this effect, but the capital
outlay would be impressive, and as a society we apparently aren't permitted to
accomplish Big Things anymore, so it's likely we stay in this weird bit of the
function for a long while.

~~~
xenadu02
Who stopped building highways? In the Dallas area we've been building and
expanding them non-stop for decades now. My experience is people have simply
moved further out, increasing traffic flowing into the newly expanded/built
roads, and overall congestion has remained constant.

But I think many of us would agree about accomplishing Big Things. Here's the
dirty little secret: the US Government has almost always funded those "Big
Things" and taxed the rich heavily to do it. The Interstate highway system was
funded by a massive (as a percentage of the price per gallon) gas tax, along
with a 90% post-war income tax rate on the rich.

Even the trans-continental railroad was funded thanks to guarantees, loans,
etc from the US Federal government (including sending the Army out shoot
Native Americans and bandits who attacked the railroads). No private entity
was willing to take such a large risk - it could have bankrupted even JP
Morgan if it went bad. Without "Big Government" support the line never would
have been built.

I'm all for bringing back much higher taxes on the rich - tax anything over $1
million income at 50%, over $10 million at 60%. Same for cap gains. Use that
money to fund massive expansions of roads, build subways under every major
city, heck start a government-funded bank that gives anyone who wants to start
a business a loan (it's what the Chinese government does).

We could do a _ton_ of "Big Things" if we were willing to tax the uber-rich to
pay for it.

~~~
ams6110
Taxing the rich simply incents them to behaviors that avoid the tax.
Government revenues increased dramatically when the high marginal tax rates
were cut. Unfortunately government expenditures increased even more
dramatically.

------
kenrikm
I would contest that many roads are not built or expanded until they are
needed and due to that the demand fills out the road on completion. If you
were to take a 3 lane road that is at 70% capacity and make it 6 lanes I very
highly doubt you would get a 6 lane road at 70% capacity. They reference a %
thought an entire city, on a more Macro level a single bigger road can indeed
ease congestion, though It may cause other roads leading into it to become
congested. The only way out of the trap AFAIK would be to build excess
capacity thought the entire system.

~~~
maxsilver
> The only way out of the trap AFAIK would be to build excess capacity thought
> the entire system.

I agree. This makes a lot more since.

The authors are taking good data, but making a big leap on their assumption to
the cause.

Roads don't "create" traffic. New roads in most major cities are never built
until the old ones are already 300-500% over capacity.

If you wait until your 500% over capacity, and then double the lanes, your
still way over capacity, so the old and new roads are still "congested". This
traffic isn't "new" \-- it was always there, you just couldn't see it, because
a 200% over capacity road, and a 500% over capacity road, looks like the same
gridlock from the sky.

~~~
mattzito
Except that roads _do_ create traffic. Your line of thinking was exactly what
drove NYC's road construction boom in the 40s and 50s - new road is built,
utilization briefly goes down, then, as soon as people realize that there's
now a faster, more convenient way to get into the city, they start using it.
Utilization goes back up.

Critically, many of those people are people who might have taken mass transit
or carpooled. They are literally new demand in the system driven by new
capacity.

Over a longer time period, there's an even deeper effect, where new roads and
perceived availability of road transit drives more people to move to
previously undesirable parts of metro areas, which increases population which
increases demand.

~~~
maxsilver
> _Except that roads do create traffic. - new road is built, utilization
> briefly goes down, then, as soon as people realize that there 's now a
> faster, more convenient way to get into the city, they start using it.
> Utilization goes back up._

That's not "new" traffic. Traffic was already critically underserved
previously, and is now only majorly underserved. The original road was 500%
over capacity, and now the new road lowers it to 300% over capacity.

> _They are literally new demand in the system driven by new capacity._

No, the demand was always there. No one went out and bought a car because a
new road was built.

These are people who we're already underserved by transportation previously,
but weren't counted (because demand so outstripped capacity that they couldn't
be easily counted originally).

> _Critically, many of those people are people who might have taken mass
> transit or carpooled._

This is a huge assumption. For instance, this can only even be possible in a
handful of places like Chicago or NYC. There is no meaningful mass transit in
the most of the major US cities to even pull traffic from.

If public transit is a good option, people will take it regardless of how many
roads exist. (Very few people purposely want to make life more expensive or
more inconvenient for themselves).

> _as soon as people realize that there 's now a faster, more convenient way
> to get into the city, they start using it._

From what you've said, it sounds like your advocating for people to willingly
make life more expensive and more inconvenient for themselves. Your saying
"new roads make driving too convenient and nice, we should take roads out so
driving becomes even more terrible than public transit already is. Force
people to make a bad choice, to avoid a terrible one"

\- -

There's absolutely no need to race-to-the-bottom on transportation. We should
build more roads _and_ build more public transit, simultaneously. When public
transit becomes cheap and convenient, many people will willing choose it. For
those who don't, new roads and additional capacity alleviates that problem as
well.

Your logic assumes that driving is inherently bad, and that we should "punish"
drivers as a result. That's terrible, there's nothing wrong with driving, and
there's no need to punish people for driving. There happen to be some bad
externalities to driving (exhaust, traffic accidents), but those problems are
being worked on (electric zero-emission cars, self driving cars, etc)

\- -

What your advocating for sounds really dangerous. Imagine if we applied this
logic to any other market:

"The internet is congested. We can't just add fiber lines, if people had more
internet speeds, they'd just use it up! We should destroy fiber lines, and cap
all internet users to 1Mbps speeds, so that people start using the Postal
Service and Blockbuster more often. "

"We can't run more clean water to the bad part of town. It might 'drive more
people to move to a previously undesirable part of the metro area'. We should
keep the water system broken -- or actually, just start slowly cutting water
off to that area. "

~~~
mturmon
"There's absolutely no need to race-to-the-bottom on transportation. We should
build more roads and build more public transit, simultaneously. When public
transit becomes cheap and convenient, many people will willing choose it."

The problem with this is that roads take room, and have externalities (cutting
up neighborhoods, noise, pollution). Some of these are being worked (as you
note) but there are no full technical solutions to these problems. People
won't stand for it.

For these reasons, your internet and water-use analogies are inaccurate
parallels.

I'm surprised you're offering these arguments. I live in LA and the opposition
to new freeways in already-built-up areas is pretty much ingrained at this
point. (Conservatives hate the destruction of neighborhoods, and liberals hate
the environmental consequences). Limited in-place widening is still being done
(with complaints) but 50 years of experience have taught something of a
lesson. People generally don't believe these wider roads will significantly
lessen congestion.

~~~
maxsilver
> The problem with this is that roads have externalities

Public Transit does too. Cutting up neighborhoods, noise, pollution all happen
with busses and light rails. The externalities are almost identical in either
case. (You can bury your light rail, but you could also bury your roads, etc).

> For these reasons, your internet and water-use analogies are inaccurate
> parallels.

That may be true, but I don't see how yet.

People oppose fiber lines all the time because "telephone poles look ugly" or
"I don't want to be in the electromagnetic field" (even though there isn't
one).

> People generally don't believe these wider roads will significantly lessen
> congestion.

To be clear, I'm not advocating for _bad_ roads. I'm advocating for _more_
roads, and there is a big difference. New freeways should be far above ground
(so that there's no division of neighborhoods) or below grade, just like new
public transit (usually) is.

I'm also _not_ advocating for more strip-mall like roads. (4-8 lane at-grade
streets typical near malls, WalMart, etc). There should be lots of big
freeways, with lots of small exits to smaller urban streets (downtown) or
smaller suburban streets.

A good example of this is the buried freeways near the Washington State
Convention Center and Mercer Island -
[http://northwesturbanist.wordpress.com/2014/02/17/lets-
bury-...](http://northwesturbanist.wordpress.com/2014/02/17/lets-bury-i-5/)

~~~
mturmon
I think we are too far apart on this one. The buried freeway idea seems like a
boutique solution for certain niche cases (the big dig in Boston is another
example).

But the freeways relevant to me (in LA) are much too large and pervasive to
put underground. It's over 100 miles of freeway, 5 lanes each way! And this is
only in the most densely built-up core. Undergrounding them is lunacy!

By the time that all got done, we'd be in robotic helicopters or uploaded.
Underground trains would be much more realistic (less tunneling for a given
throughput), but even so, we have to be content with aboveground light rail.

------
nardi
So more lanes don't reduce congestion, but this article ignores the fact that
they obviously DO increase quality of life, by giving people the freedom to
live and work where they choose. We should build more lanes for that reason
alone. The reason congestion doesn't get better is simply that there is pent-
up demand for driving. The solution isn't "tough luck, adjust your life to fit
the traffic." It's to build more lanes, so people can choose to live the life
they want to live.

~~~
JPKab
By all means, then pay for YOUR ROADS which get YOU to YOUR MCMANSION
SHITHOLE. Those of us who choose to be more rational about where we live,
rather than adhering to an absurd ideal of a homestead that simulates a farm
while having a modern, urban job far away shouldn't have to finance your silly
fucking lawn and your boring, awful neighborhood.

I have 2 kids, and I've made urban living work. Courtesy of Virginia's former
governor (now on trial for felony corruption charges) our roads are no longer
funded by gasoline taxes, and are instead funded by a sales tax that people
like me, who walk to work, have to fucking pay. If I had my way, all of you
commuter idiots would have to pay a toll for all roads. Its absurd that I
can't ride a subway for free, but you get to use public infrastructure while
the rest of us pay to maintain it.

Your "freedom to live and work" is actually a freedom to take from urban
people and give to yourself to finance your unsustainable, silly lifestyle.

If you want to live in the country, then fucking work in the country. Grow
something other than a useless, decorative plant that requires extensive
fertilizer and watering.

The solution:

Tough luck, adjust your life to your dumbass decision to live in the suburbs.

~~~
TheCowboy
As someone who mostly agrees, and has found other posts you've made to be a
useful contribution, I think this one strays from that.

Even if it's personally satisfying, no minds are being won here.

~~~
JPKab
You're right. Thanks for the much needed reality-check.

------
DigitalJack
I have only read the linked article, not the study, but it seems to me to be a
bizarre conclusion that if capacity is increased and utilization remains at
maximum, that the capacity caused the utilization.

It seems to be a much simpler scenario that demand far outstrips capacity, and
until you can meet the demand, saturation every lane added will continue to be
saturated.

I'm sure amdahl's law applies to lane adding here, on top of the fact that all
the highways I've seen merge from one side or the other. I don't think I've
seen any that merge in the middle, though I guess they probably exist.

------
tunesmith
It's interesting that they make the point that congestion pricing will induce
people to take alternate routes.

The recent update to Google Maps seems to do the same thing. It's much more
proactive now about suggesting alternate routes. Here in Seattle, I recently
bypassed I-5 by taking an astonishingly complex and twisty route that was all
prompted by Google Maps, and I got to my destination five minutes sooner than
Google was estimating I would had I stayed on I-5 (although that's impossible
to verify since traffic congestion changes throughout the duration of a
drive).

All that said, while it was fun (also especially when I avoided a Tacoma I-5
snarl that I hadn't previously known how to avoid), I don't think we actually
want to redirect highway drivers onto local streets. Local streets aren't
designed for highway overflow; they're designed for local traffic.

Isn't the real answer to design more decentralized town areas so people have
less reason to drive long distances, for reasons other than recreation?

~~~
judk
Try the math. For a given number of people, centralizing reduces everyone's
commutes. The key is to not separate housing from commerce and business.

------
peter_l_downs
Funny to see this on the HN frontpage – the Downs who originally suggested the
"fundamental law of highway congestion" being confirmed in the paper [0] is my
grandfather. Thanks for submitting this, it's very interesting work.

[0]
[http://www.nber.org/papers/w15376.pdf](http://www.nber.org/papers/w15376.pdf)

------
DINKDINK
Driverless cars have the vast vast potential to fix traffic congestion
problems. Traffic mainly results from humans' inability to gauge the spacial
and speed based tolerances required to prevent braking and as a result sending
a backward brake wave through the cars behind it. Add to that fact that there
are no game theory advantages to a single driver to driving properly (other
than an altruistic realization that if you decide to drive with better
tolerances and other people do the same, the congestion is abated)

~~~
nulltype
That seems dubious. There are a finite number of cars you can get on the road
at a given speed. If the total travel time is roughly a constant as this
article implies, autonomous cars will be equivalent to adding a few more
lanes, meaning there will be no long-term change.

~~~
DINKDINK
Traffic results when car densities pass a certain threshold and the speed the
cars are traveling at prevents humans from being able to react in time or
appropriately.

You might have even seen this phenomenon in real life: Driving on a highway,
suddenly you get stuck in traffic. As you pass through the traffic zone, there
are no cars pulled over, no accident, no disruption in the quality of road.
What most likely happened was that someone accidentally slammed on their
brakes which caused an increase in car density. If there are enough cars that
are in bound to this traffic zone before the density can disperse, the traffic
zone will persist.

Also notice that traffic zones often appear in situation where there's a
positive increase in elevation. What happens is that if people aren't using
cruise control (or their cruise control, control system isn't tight enough)
their speed will decrease as they ascend the hill, causing some congestion and
as like if the density of traffic is high enough, the cars behind them will
have to slow down. You may think that if the cars behind them are also
ascending the hill they'll also slow down in the same way but some cars may
use cruise control while others don't (resulting in congestion) or the
differences in each car's torque, power-output, efficiency curves differ
causing each to slow down at different rates (often leading to the least
capable car governing the rate)

Use a worst-case scenario to analyze. Assume you have a network of diverless
cars all linked together that maintain equidistant space between each other.
If a new cars needs to join their network / pack the minimum amount of delay
that the cars (behind the entering car) need to encounter is the (Length of
the incoming car + gap tolerance between the other car) / (the sustained speed
of the pack) =25/5280/65*3600 ~= .25 seconds per car. Now do a thought
experiment that the high way you drive on was completely full (like we said in
our original problem statement) do you think if you added one additional car
to the highway, would everyone's (who's downstream of the merge) commute time
be only increase ~.25 seconds? I'm very confident it's be much more than that.

Traffic management is a task that needs high coordination, cooperation and
reaction times above what unassisted humans are capable of.

------
xvedejas
A phenomenon very similar to "induced demand" was observed in 1865, when
increased efficiency in coal consumption lead to increased demand for coal.
It's called Jevon's paradox:

[http://en.wikipedia.org/wiki/Jevon%27s_paradox](http://en.wikipedia.org/wiki/Jevon%27s_paradox)

------
zmmmmm
Yet when I visit a small country town with a giant road through the middle,
there is still no traffic there. If big roads induce traffic independent of
any other factors then this should not be true - the mere presence of the big
road should have created traffic.

While I understand there's a really point to this paradox (it really happens),
I hate the simplistic conclusion people reach that it is always wrong to make
a road bigger. Sometimes _you really do need a bigger road_. Sometimes you
really need more public transport or something else. It's complicated, and we
need better models of it. But reducing it to one line slogans doesn't help
that.

~~~
nickonline
That's kind of the point made about halfway through the article where he
states if you expand a road to 100 lanes you won't ever see any traffic.

In those country towns with a population of 30,000 but a super road through
the center that could carry 100,000 people a day the road _is_ the same as if
that 100 lane highway had been built in a major city.

In the article they state that there are more factors at work but they do need
a title for the article that will draw people to read it.

~~~
astrodust
I think highways like the 401 in Toronto prove that the "100 lane" theory is
pretty much bullshit.
[https://en.wikipedia.org/wiki/Ontario_Highway_401](https://en.wikipedia.org/wiki/Ontario_Highway_401)
It's arguably the busiest highway in North America based on a number of
metrics, even more volume than LA's perpetually busy Santa Monica Freeway.

They've been expanding it ever since they've built it and in parts it is 25
lanes wide. It's slammed all the time. Traffic jams at 3am aren't unheard of
if they're doing road work and it's slimmed down to half capacity.

It was once merely an 8 lane highway, so the idea that tripling or quadrupling
the size of a highway magically makes traffic jams go away is so far from the
truth.

There's a parallel highway running north of it that's paid by tolls which
isn't as busy, but only because they can adjust pricing according to demand.

------
duncan_bayne
Counterargument here: [http://pc.blogspot.com.au/2014/06/more-roads-doesnt-
mean-mor...](http://pc.blogspot.com.au/2014/06/more-roads-doesnt-mean-more-
traffic-jams.html)

"By comparison, building expensive transit systems aimed at getting people out
of their less-expensive cars generates zero economic benefits if it generates
no new travel. Only new travel generates economic benefits, so people who
argue that new roads induce new travel are actually arguing that new roads
create economic benefits.

If congestion is the issue, then–as Mann briefly mentions–the solution is
congestion pricing. But Mann doesn’t understand the difference between true
congestion pricing and New York City’s proposal for cordon pricing. Cordon
pricing is more a way of raising revenue to fund urban boondoggles than a way
of relieving congestion.

Even UC Berkeley planning professor Robert Cervero believes that the induced
demand argument is “wrong headed.” “Road investments by themselves do not
increase volumes,” he writes. “Only by conferring a benefit, like faster
speeds, will traffic increase.” Provided that benefit is greater than the
cost–something that could be assured, Cervero says, through proper pricing of
roads–then it is a good thing."

------
chsonnu
Unused road space is staring everyone in the face and only a small percentage
of commuters are using it: motorcyclists. If you just took 10% of the cars off
the road and had them riding and lane splitting instead, congestion would be
reduced exponentially. The good news for Californians is that lane splitting
is actually legal unlike every other backwards ass state.

------
larrydag
Dallas is building a congested demand pricing project for the I-635 corridor.
They are calling it managed toll lanes.
[http://www.txdot.gov/business/partnerships/current-
cda/635-l...](http://www.txdot.gov/business/partnerships/current-cda/635-lbj-
cda.html)

~~~
alistairSH
I-495 through the VA side of the DC suburbs uses High-Occupany Toll lanes -
demand pricing on top of HOV lanes. If you have passengers, you can use them
for free. If you're solo, you pay the toll. They use a switchable EZ Pass
transponder to make it work without toll booths at each end.

Colloquially, they're referred to as "Lexus Lanes".

As far as a I can tell, they haven't done much to reduce congestion on the
non-toll lanes. But, if you can afford $12/day (peak rate, round trip) for a
10 mile stretch of interstate, you get to avoid the dirty, unwashed masses who
are stuck in the poor lanes. :)

~~~
koenigdavidmj
The concern when this got deployed in the Seattle area is that it would be
poorer people who are most likely to use these. Example: somebody trying to
get to the daycare by 6PM so they don't get charged by the minute for being
late.

~~~
crazy1van
Why is this a concern? It sounds like a completely rational decision for
someone of any income level to pay money for a faster trip to avoid an even
great amount of money in fines...

------
moron4hire
I live inside the Washington D.C. beltway in Alexandria, VA. Traffic here in
town is slightly better than what I had gotten used to in Philadelphia, but
that's likely because A) I never have that far to go and B) I never drive
during rush hour anymore. In the District, it's a fucking Boschian nightmare.
DC typically ranks 2nd or 3rd worst traffic in the country, duking it out with
LA and Miami.

And all around me, as I look out my windows, all I see are skycranes build
condo projects.

On my walk to my local coffee shop, I see a political campaign poster touting
the candidate will work to block some proposed parking garage project that I
never understood why old people hated.

There is a new metro station going in less than half a mile from my place.
Except it won't be done for another 5 years or something. And really, the
other nearest station is only a mile away over flat road. I don't understand
putting metro stations less than half a mile from each other. That just seems
more likely to _cause_ traffic than it is to alleviate it, as it increases the
latency of trips.

There aren't any major road projects going on. There are one or two projects
to fix up a few ramps that were crumbling. There is something about an express
lane all the way to the Dulles airport. But nothing about the 95 expressway
seems to be addressed.

Clearly, someone is planning to pack a LOT more people into this area, but has
given no thought whatsoever where to put their cars, either while in use or
not.

So I've just accepted that this is reality now. There is absolutely no reason
to complain about traffic, because nobody is doing anything meaningful about
it. I try to work my life to not be involved with it at all. I do most of my
shopping online. I am a freelancer who works 100% from home. I live in walking
distance of a bar and a coffee shop, and I'm even cutting back how often I go.
Unless I can finally convince my wife to move out of this place, I'm not
traveling anywhere during daylight hours.

------
jrobbins
I see it as basically Malthusian: people will keep driving until it is so
unpleasant that they don't want to do it any more. The tipping point for most
people is around 45 minutes. Here's a book with a footnote that mentions that
the same 45-minute rule applies worldwide and though out history:
[http://books.google.com/books?id=uuqIA-
ce1CoC&pg=PA408&lpg=P...](http://books.google.com/books?id=uuqIA-
ce1CoC&pg=PA408&lpg=PA408&dq=ancient+romans+commute+45+minutes&source=bl&ots=W_4
--bDOo5&sig=uNYXKSxadR3pUeZ3epHuKgvI0GQ&hl=en&sa=X&ei=xLGxU-
vIHoiTqgaUhIDYDQ&ved=0CDEQ6AEwAg#v=onepage&q=ancient%20romans%20commute%2045%20minutes&f=false)

------
gweinberg
Dolts like the article author completely miss the point. Yes, the number of
people on the road will increase as we add lanes, but that doesn't mean that
adding more lanes is useless. More people are able to get where they want to
go, that's a good thing.

~~~
gerbal
Building alternative high-volume modes of transportation is more effective
than building larger roads.

Adding more lanes is useless from a urban planing point of view because it
doesn't alleviate congestion.

------
cyphunk

        Finally, businesses that rely on roads will swoop into cities 
        with many of them, bringing trucking and shipments. 
    

Indeed, roads are most often built to bring in new large corporations that
create jobs. Depending on how one measures "quality of life" this could be
considered a very good thing.

I was expecting something more interesting such as the correlation to car
driver behaviour and inefficiency with stop-go traffic when not leaving a
buffer in front of the next car (something that was written up very well a
year or so ago) and how this logic is effected with wider roads. Instead, got
some pretty worn out theories.

------
jusben1369
I'm not sure I'm a buyer of the congestion demand pricing. There's a very real
cost already involved in traffic. Time lost in the car, quality of life,
stress. Anybody who lives in the Bay Area, LA, NY, DC understand that timing
your entire life around traffic is the regional pastime. So the argument then
has to be an incremental one. If we then layer a more direct money tax of some
kind on top of all the crap that already exists then that will be the straw
that breaks the camels back and gets enough people off the road. Hmm.

~~~
CanSpice
That's a sunk cost though. When someone gets in their car to drive somewhere,
they don't think "this trip is going to cost me $7.50" because they pay for
their gas at a different time, they pay for their insurance at a different
time, they pay for repairs at a different time, and vehicle depreciation is
largely invisible. They don't equate time lost to money lost either.

However, if you have a big visual reminder that the road you're driving on
will cost you money as soon as you drive on it, then people will be less
likely to either take that route or drive altogether.

~~~
jusben1369
I hear you but I'm going to respectfully push back. When you live in a
congested area you really do plan much of your professional and personal life
around traffic. When to start work. When to leave work. When to schedule a
meeting. When and where you'll go this weekend/vacation/kids. So this will
make it more painful but it's hard to know how much this will be the final
tipping point.

------
phkahler
These guys are partially idiots. Obviously there is more demand than road if
use is directly proportional to supply as they claim. The problem is the way
we design cities and lay out the roads. A regular grid where we put STOP
lights? seriously? Go, stop, go, stop. And then we put businesses right on the
corners to increase congestion right where it's already bad. When cars get
tested for EPA MPG ratings, the average speed on the city drive cycle is
slightly under 20mph due to all the stop and go. Hybrid cars get better city
mpg than highway by using regenerative braking to recover energy from all that
stopping and making drag the dominant factor. I don't think traffic circles
are relevant, but designing the layout to minimize disruptions to flow
altogether. I've been contemplating this a lot, but can't write it all here
right now. Imagine if every drive were 10-20 percent longer distance, but you
could average twice the speed over the journey! You'd save gas and time. And
if your journey takes less time, that's fewer car-minutes on the road which
means less traffic and they could have fewer lanes. The problem is even if we
could do the design correctly, nobody is going to build a city from scratch -
except in China maybe.

~~~
andys627
It seems like you're assuming that the only priority is moving cars around -
not walkability or livability. In other words it seems you're assuming the
only purpose of the built environment is to move cars. I argue that it isn't
and in that case we should measure other stuff besides moving cars efficiently
when building our cities.

~~~
phkahler
No, I advocate efficiency as a goal weather it be cars, public transit, or
something else. Personally I'd like easy access to both. But public transit is
only viable with high density and I don't like the way we do dense either.

------
melling
They're also an eyesore.

Not to worry, over the next several decades large cities will build out
effective mass transit systems. High-speed rail will eventually come to
America after years of debate.

Look to China to lead the way. What's this low-speed maglev that they're
building now?

[http://usa.chinadaily.com.cn/epaper/2014-02/19/content_17291...](http://usa.chinadaily.com.cn/epaper/2014-02/19/content_17291903.htm)

~~~
pdonis
_over the next several decades large cities will build out effective mass
transit systems_

Which, as the article points out, won't fix the traffic congestion, because as
some people switch from driving to mass transit, other people will take their
place by driving when they previously walked or just didn't make the trip at
all. So mass transit can increase the total number of trips made, but it won't
decrease road usage.

~~~
personZ
[http://www.theonion.com/articles/report-98-percent-of-us-
com...](http://www.theonion.com/articles/report-98-percent-of-us-commuters-
favor-public-tra,1434/)

It is the onion, and is flippant, but as a general belief it touches upon a
basic truth -- everyone would love if everyone else used public transit,
leaving the roads available for our use.

~~~
_delirium
This is occasionally used as an argument in favor of cheaper or free public
transit: that even from a self-interest perspective, it makes sense for road
users to subsidize public transit, as a way of effectively paying other people
to get off the roads and out of their way. However most road users don't seem
to see it that way.

------
fataliss
I wish, LA had a good public transportation network but it doesn't. I used to
take the bus, I had to change twice and spend at least 1h traveling, while it
takes me 12 to 20min using my car (20min on exceptionally busy days). It
probably is one of biggest city that doesn't have an underground metro! I
guess that's one of the rare thing I miss from NYC. Being able to move fast
without owning a car!

------
_Adam
The article fails to follow the logical process to the very end. What isn't
being asked is: why are humans using that road when they weren't using the
smaller road before?

Humans don't just drive for the sake of doing so. They drive because they have
the need to do so. Building roads lowers the perceived time cost of driving,
so more people drive, and more people drive at the time that is most desirable
to do so. In some cases this results in increased congestion, but if the need
of the population is met or exceeded, then the result is smooth traffic flow.
Even if the bigger road is more congested, it may still have a greater net
traffic flow, and that increased flow results in greater economic and societal
good.

For example, because of new highway XYZ, I can now work somewhere that was
formerly too far a commute.

The problem isn't solved by building smaller roads, it's solved by building
even bigger roads, or building roads in a more optimal fashion (selecting a
route for a new road that matches the transportation needs of the population).

------
logfromblammo
This is exactly the sort of thing that I don't want a politician to read.

A study finds a correlation between construction of new roads and increase in
driver miles. A policy-maker, never one for logic, transmutes correlation to
causation. Now, it may be that they assume that increased demand for travel
causes road construction, and assign resources to reduce the total cost for
each trip. Good for them.

But they may also assume that more roads cause more travel, and decide to
prevent trips by destroying roads. Boo. You could as easily prevent water from
flowing downstream by building a dam. Then your stream becomes a reservoir,
the downstream flow rate reduces while it fills, then the reservoir spills
over the dam at the same rate it flowed before.

People want to move around. They want to travel freely between the places they
can earn money, the places they can spend it, and the places they enjoy
keeping their stuff. Making the travel more difficult makes them unhappy,
while making it easier makes them more content. For the most part, the desire
to move minus the cost of the trip results in economic activity. If that
number is zero or negative, people stay put, and don't add to economic
circulation.

Human movement is an economic engine. You can add friction to it and generate
more heat, or you can remove friction and extract work instead

Generally speaking, you want people to take more trips, and you want the cost
per trip to be as low as possible. That doesn't necessarily mean building
more, wider, and longer roads. You may be able to get better results by siting
the popular destinations more closely to each other, and ensuring that the
routes between them are direct, non-viscous, and non-turbulent.

When you do something stupid like make 3000 people work in one building
complex, far away from homes or other businesses, and have everyone sleep in a
suburban bedroom community, far away from jobs and shopping, yes, the road
that is the best available route between them will be packed every single day.
You cannot economically reduce traffic by narrowing that road. The cars you
see on it will go down, but that is because people quit their jobs or moved
their households over the arduous commute. They went somewhere else, and will
be earning and spending there, instead. It would be better to simply put the
homes, businesses, and offices closer together, and diffuse the obvious trips
onto roads in such a way that they are neither over or underutilized.

~~~
bcoates
> But they may also assume that more roads cause more travel, and decide to
> prevent trips by destroying roads.

Politicians in the city I live in are literally doing this, installing
"traffic calming measures" (destroying perfectly good road lanes that were
just resurfaced)

I believe phase two involves generating clean energy by harnessing the power
of Bastiat spinning in his grave.

------
dasil003
I witnessed a nice microcosm of this demonstrating how fast the shift occurs.

Every day I cycle commute up the London A24/A3 (CS7) corridor. On the first
day of the first tube strikes early this year, the congestion was insane. I
mean the worst traffic I've ever seen in my life. An ambulance was literally
stuck in traffic and no one within earshot of the ambulance able to move their
vehicle enough for it to get through.

But then the second day of the strike traffic was a bit on the heavy side but
mostly back to normal. I think a huge number of people realized that it was
actually pointless to even attempt to go to work unless they were walking or
biking. This effect even carried over to the second tube strike a month or two
later.

------
lelf
The actual paper
[http://www.ademloos.be/sites/default/files/meccano_docs/The_...](http://www.ademloos.be/sites/default/files/meccano_docs/The_Fundamental_Law_of_Road_Congestion_Evidence_from_US_Cities.pdf)

------
drawkbox
Sounds a bit like Parkinson's Law:
[http://en.wikipedia.org/wiki/Parkinson's_law](http://en.wikipedia.org/wiki/Parkinson's_law)

"The demand upon a resource tends to expand to match the supply of the
resource."

------
sologoub
This article seems like a gross oversimplification. There are a lot more
variables at play here than just what people tend to do with extra capacity.
Terrain and flow dynamics, as well as driver behavior, have a lot to do with
it.

Take 405 in West Los Angeles for example. On one side it has the Sepulvida
pass with very steep decent going south and ascent going north. It is crossed
by I-10 going to Santa Monica and Downtown, a little further in 90 goes to
Marina del Rey, and then exits for LAX.

If you examine this section as an example, you have number of people either
trying to get in or pass through this section during commuting hours. From the
north, the sepulvida pass makes people slow down as they climb the hill. Not
exactly sure why, but many drivers seem to be afraid of it. This recoils
through the rest of the traffic, as each incremental car slowing down results
in the car behind it slowing down slightly more.

Once you get down the hill, you have people exiting and entering with very
short distances to decelerate or accelerate, causing more slow downs.

On the other side, you have a similar dynamic, but people are also trying to
merge to or from 90 and I-10. With majority of the traffic heading either to
Santa Monica, West LA, Century City or Hollywood/Downtown/something in
between.

The city has recently completed a major expansion on the 405 in that area
adding a carpool lane, but more importantly changing how you merge to/from
several of the exits, including Wilshire blvd and I-10.

In my observation, the carpool lane did relatively little, but the smoothed
exiting/entering with enough time to accelerate shifted the bottleneck from
before Wilshire blvd, frequently spilling past the 90, to no ending around
Wilshire.

The flow restriction now seems to be the dreaded 101 interchange, with a huge
amount of traffic stuck in the Sepulvida pass. As the result, I can not get
from the 90 to I-10 in about 10 mins, whereas before it was easily 30.

Point being, that if you maintain road size (or marginally improve it) and
optimize the flow, you get a lot better returns.

~~~
gr3yh47
apparently, correlation is equal to causation[1]

[1]entire article

~~~
moskie
I don't think that applies. Isn't the point (or one of the main points) of
building more roads to make traffic congestion better? The study in this
article shows that that doesn't pan out.

------
Corrado
What about a smartphone app that helped you avoid the most congested roads. I
think Waze does something like this today and I'm sure that Google Maps can as
well. We just need to have it integrated into the system so that we don't have
to think about it.

I think this is where projects like Andriod Auto & iOS CarPlay come into play.
Just jump into your car and say "Take me to Julia's house" and the route will
be mapped out for you. I would love to not have to figure out the best way to
get to the mall on a busy Saturday afternoon! Even better, an auto-driving car
will actually take care of the moving bits as well as planning your route.

------
transfire
What a bunch phooey. Just more peddling of flawed studies to promote increased
taxation.

If you want to reduce congestion try the obvious. 1) Mixed zoning, allowing
more residential and retail to be close together. So people have less distance
to travel. 2) Raise speed limits where possible so people can get to their
destinations faster. 3) Build for the future. Don't just add a lane or two,
add six. 4) And yes trains, do help. The problem in the States is that we
hardly have any. Only the major metro areas have any sort of adequate rail
system and even they are fairly slow, limited and antiquated. Which brings me
to my last point: 5) Consult with Elon Musk.

~~~
xenadu02
I'm sorry but you are simply way off base. When a road is expanded, it does
temporarily shorten commute times and reduce traffic. But that makes the cheap
land farther away from everything more desirable, causing people to move out
further, increasing traffic. Those new suburbs require a _massive_
infrastructure investment to install water, sewer, gas, electricity, etc. Not
to mention building surface streets, schools, libraries, shopping centers,
etc.

We've been building roads at a massive clip around the Dallas area, sprawling
out over huge suburbs, many of which support mixed development (as does the
city of Dallas itself). When I first moved here, the previous two lane highway
had just been turned into a six lane toll road and there were no traffic jams,
not even during rush hour. It's been 8 years and now we have stop and go
traffic every day for about a 30 minute window and that window continues to
grow larger.

If you think about the design of roads it should become clear why this
happens... You have many on-ramps dumping cars into a fixed set of lanes. If,
at any point, there are more cars that want to enter than there is room
traffic must slow to accommodate them. In reality it happens before the road
is full as people leave space for braking, etc. When that happens at _any_
point, it creates a wave of slowed traffic that begins to ripple backwards
from that point, meaning anywhere further backward that is close to capacity
begins to jam up, making it even more difficult for new vehicles to enter the
roadway, amplifying the wave even more.

Even if demand were 100% evenly spread out (which it never, never will be
simply by the fact that brand new areas have empty fields or wooded lots - it
takes time to build offices, start businesses, etc), the friction of merging &
exiting the highway would eventually require more cars to exit than are
entering, the exact opposite of rush hour conditions.

Building more lanes merely delays the inevitable; that's assuming you can,
which in Dallas is impossible - most of the current roads (and 100% of the
worst congested ones) would require tearing down skyscrapers or 100% tunneling
/ elevated highways because there is no more space.

------
StillBored
I think studies which measure traffic congestion in the US based on road
building over the last couple decades IMHO are flawed.

That is because I believe how and where you build the road is more important
than how much road you build. For example, where I live the main roads in the
city proper haven't been upgraded in the last 40 years. Yet, new roads
funneling drivers from farther and farther out are being constructed all the
time. This simply means that the first 1/2 of many drivers commutes involves
sailing along a new road until they hit the old roads, and then puttering
around at 5mph (or worse) for the last 5-10 miles of the journey.

------
gldalmaso
>> _If we gave drivers some extra incentive to avoid the most congested hours,
we could better utilize the roads’ capacities._

There is already enough incentive, the incentive is to avoid seeing your hours
waste away on traffic. Most people don't really get to choose their hours,
with or without incentive, otherwise they already avoid the most congested
hours. So the suggested incentive doesn't really make a difference when it's
not a matter of choice, except by taking money away from people without adding
any value.

~~~
taejo
So we need to incentivise the people who set the hours.

------
gtCameron
Weird title, seeing as how the article states that bigger roads do not make
traffic worse, it stays the same:

>> New roads will create new drivers, resulting in the intensity of traffic
staying the same

~~~
jusben1369
Good point. And it's still not completely clear that the roads are keeping up
with the growth vs pulling it in. There were a couple of good points around
larger interstate type services picking your town for HQ if you have extra
capacity but in general it still seems too abstract.

------
moron4hire
I wish there were a starter packet for using the metro. I hate it when people
say, "where do you want to go? Oh, that's simple, you just take the Orange
line to Such-and-such station. Why couldn't you figure that out? It's so
simple." No, that is not simple. That's an insider's language designed to call
out the outsiders. I get there and there isn't just an orange line. The orange
and green lines overlap. Don't get on the wrong train at the right terminal!
Or maybe it's like the purple line, where you have to take the orange line to
get to it, and everyone else already knows this, but they don't tell you that,
they just say "take the purple line" and I'm left standing there freaking out
that I can't see a purple dot on a sign in a poorly-lit cavern.

If I drive somewhere, all I need to know is where it is and where I am and I
can eventually get there within 50% of the normal time to get there. Let's
take this road that points towards where I want to go. That didn't work? Okay,
let's take the next road that points to where I want to go. Unless you're
driving around the Pentagon, which I'm fairly certain has had its road systems
designed into the shape of a PENTAGRAM, then that will get you to where you
want to go in the majority of the US.

And grand total is still faster than walking to the metro, waiting in line for
the train to show up, and waiting for it to stop at every spot in between.

~~~
zaphoyd
Google maps / transit routing smartphone apps do a pretty good job of this.
I've not had trouble coming into a new city, asking Google maps to give me
mass transit directions and just following them.

Most cities have real time bus/train trackers now that help you plan when to
leave so you don't have to wait long.

~~~
moron4hire
Yes, Google Maps is how I manage it.

------
aaron695
This article is rubbish

> What’s Up With That: Building Bigger Roads Actually Makes Traffic Worse

> For instance, Paris in recent decades has had a persistent policy to
> dramatically downsize and reduce roadways. “Driving in Paris was bad
> before,” said Duranton. “It’s just as bad, but it’s not much worse.”

Bigger roads are worse, and smaller roads are worse?

There's a point here somewhere but they've failed to make it.

~~~
emj
I guess they get more foot traffic, and living streets (more shopping/social
life etc). If you get that and less cars in traffic I guess I see a win there.

------
CamperBob2
Then clearly we can make traffic flow more smoothly by shrinking existing
roads. Right?

What? No? It doesn't work that way? Hmm, what a coincidence, it appears we're
already at the sweet spot on the traffic-flow Laffer curve.

Either that, or what the authors of the study are trying to optimize is very
different from what the typical driver is trying to optimize.

------
frogpelt
I'm a huge fan of toll roads. And I really like charging for use at certain
times.

Perhaps you could reduce rates for each passenger in the vehicle. Maybe a
four-passenger vehicle gets to drive free anytime. This encourages car pooling
for those who can't afford to pay the tolls.

In fact it may create new jobs.

------
skriticos2
Well yes, people are irrational.

I personally think that a lot of jobs today don't justify driving around at
all. What difference does it make if you code in the crowded building of your
employer or at home and use tele-conferences to talk with each other? Maybe
you would even be more productive if you got rid of all the stress caused by
commuting around a substantial portion of the day.

I guess a good chunk of the office work done today could be replaced by remote
work, but employers insist on everyone to get into the car, commute and
thereby congest roads and burn up non-renewable petrol.

I am seriously wondering why the working population don't bill the time and
expenses of commuting to the employers? Most entrepreneurs do. You pay
$50-$100 for the plumber to come to your place (just to come there, work is
billed extra). Why not office workers?

------
brianstorms
This is nothing new. Read Robert Caro's 1974 Pulitzer Prize-winning book THE
POWER BROKER if you wanna know about roads and highways and freeways and how
expanding them only makes traffic worse.

------
legohead
I've always thought something is definitely wrong with the way we think about
roads when car pool lanes end up just as busy/gridlocked as the rest of the
road.

------
bane
I feel like there's a cause and effect relationship being presented here that
isn't necessarily true, even if the correlation is true.

------
mcone
_It’s the roads themselves that cause traffic. The concept is called induced
demand, which is economist-speak for when increasing the supply of something
(like roads) makes people want that thing even more._

So contrary to popular belief, invention is actually the mother of necessity.
The question now is how best to take a systems approach to promoting
alternative forms of transportation.

~~~
scarecrowbob
"The question now is how best to take a systems approach to promoting
alternative forms of transportation."

If the principle, holds, obviously: build more.

~~~
33W
I think that it might hold, at least for me. The biggest obstacles to my use
of public transportation is the first mile and last mile, and the regularity
of trips.

Using Google Maps as my source, a trip home will take between 1hr, 3min to
1hr, 30min, and still includes driving for the last mile. Granted, this is San
Antonio, which is certainly a driving city. The same drive home is 14-17
minutes, depending on route.

In my calculus, drive vs. public trans. is a balance of which sucks least.
Right now, I would say that the cost and altruism aspect of public trans.
would allow it 200% of the suckiness allotted to driving. All else being
equal, I would need a public trans. trip of ~30minutes or less.

------
ehosca
Yes, I’ve been stuck in traffic on 405, but it’s not like you never get
through.

------
uint32
Also: bigger/faster computers makes programs bloated/slower.

------
anoxic
This actually makes sense in an unintuitive way.

------
vermooten
well duh

