
A broken algorithm that affected American transportation - panic
https://www.vice.com/en_us/article/v7gxy9/the-broken-algorithm-that-poisoned-american-transportation-v27n3
======
rikroots
I met another faulty transport planning algorithm 30 years ago.

Background: my first job in the UK Civil Service was as an admin assistant (I
did the filing) in the Highways Contracts division, Dept of Transport. My
team's job was to let the contracts for developing plans for new/improved
national roads across England.

The Algorithm: roads cost a lot of money to build; every proposed route had to
demonstrate significant value for money through a cost-benefit analysis for
each project, considering a number of different detailed options for the new
or improved road. One of the main costs was how much money needed to be spent
on buying and securing the land, and compensating the owners for loss of
business, etc. In cities and towns, this favoured putting bypasses through the
poorer parts of the (sub)urban environment. In more rural areas it favoured
routing roads through less productive farmland. The least productive land was
land that wasn't being farmed or mined. Routes put through these areas would
be given an acquisition cost of £0/meter[1]

... Which is why in 1993 the Government settled on developing an improvement
scheme for the A303 which put a new double-lane carriageway straight through
the middle of Stonehenge.

The proposal didn't go down too well. 30 years - and several administrations -
later, the Government is still trying to get the proposal through planning[2]

[1] - Though in fact highway lengths were still measured in 'chains' and
'links' back in the early 1990s:
[https://en.wikipedia.org/wiki/Chain_(unit)](https://en.wikipedia.org/wiki/Chain_\(unit\))

[2] - Current proposal for the project:
[https://assets.highwaysengland.co.uk/roads/road-
projects/A30...](https://assets.highwaysengland.co.uk/roads/road-
projects/A303+Stonehenge/Environmental+Non+Technical+Summary.pdf)

------
KingMachiavelli
As some others have mentioned, I don't think that induced demand or the
failure to prevent congestion are failings of the model itself. A congested 5
lane road still has a higher throughput than a congested 2 lane road.

However, the largest problem I see which the article briefly touches on is the
failure to even consider building something besides a freeway. A `correct`
model should be screaming to build public transport.

However, consider the following circumstances:

1\. As it is many people are forced to have a car even if public transport can
serve their main commute but often public transport is more expensive than the
marginal cost of driving a vehicle (i.e gas + upkeep) so they choose to drive
unless the congestion is extreme (i.e one of the worst commutes in the US).

2\. Even if public transport is pretty decent (commute + groceries), they just
happen to already have a car because their previous location did not have
public transport. So we are back at #1. Or I don't know if I'll move in a year
or two so might as well keep the car.

3\. OR now that I have a car , I would probably not want to have to pay for
expensive parking (& housing) in an area with public transport plus now I'll
have to pay a mechanic a premium to even change the oil. So instead I live
further away thus reinforcing the need to keep the car.

4 & etc. I need to travel >50 miles (skiing, hiking), renting is a pain and
long trip ride sharing is expensive. Groceries are easier to do with a car
especially when buying in bulk (Although, if/when I can get Costco delivered
same or 2-day with perishables at <=10% premium, then this is a moot point).

Cars are pretty (at least marginally or per mile) cheap in America and we do a
very poor job making the alternatives attractive if not impossible. Anyone who
has a car seems to drive it even if public transport could be used (again
outside of super specific commutes in a few cities). Until we can either make
car ownership/use more expensive or greatly increase the practicality of not
having a car at all, anticipate having a car and being stuck in traffic at
least part of the time.

~~~
m463
So I have a weird opinion - cars are cheap, and give us time.

If your time is worth little, public transportation will work. But if you want
to get from home to work and back, the car will be quickest. And if you want
to go to the grocery store on the way home, no public transportation helps
with that.

There are a few modifications of that.

If you have to get to work and you're not in a rush and you have something to
do along the way like listen to a podcast or read a book, then that might be
slightly different, because you're living a bit. (although podcasts work in
the car if you are not against driving + listening - some people are)

Public transportation works really well when the roads are full full full.
Getting from one side of Mexico City to the other quickly during rush hour is
possible with the metro, not possible in a car.

~~~
adrianN
That's true of your personal car (if you're lucky), but cars in general are
expensive and don't give us time. They just increase the distances people are
willing to travel, and as a city-planning and economic side effect, increase
the distances people _have_ to travel. All while having terrible side effects
on the climate and our health.

------
nicolaskruchten
I broadly agree with the article, but one point where it falls short is that
it doesn't mention that the 4 stages of the model can be (and sometimes even
are!) iterated in various ways to account for the way real people actually
behave: modellers in the 21st century aren't quite as naive as all that (and
probably the ones in the 50s weren't either but they had less data/computer
power).

For reference, the four stages go like this: you start with "trip supply and
demand" by zone, then inter-zone trips are generated by matching those up,
then mode choice is computed per trip based on cost and travel time priors,
then assignment to the network which results in actual trips and computed
travel times based on route selection and congestion.

The travel times can then be fed back into mode-choice and iterated on: people
will make the transit-vs-car choice differently based on the relative costs
(in time and money and inconvenience) so iterating the last two steps can go a
ways towards modelling that equilibrium.

Folks can exert some amount of choice around which trips they make (as
mentioned in the article) and where they work, based on how easy it is to get
there, so feeding the travel costs back into trip-generation can account for
some of that, and over a longer horizon, both workers and employers can exert
some control over where they live/site their facilities, so all 4 stages can
be iterated as well.

None of this is perfect, and it's not always done, and the rest of the
article's points stand, but I just wanted to say the modelling is not all that
primitive :)

Edit: I studied this stuff in university 15 years ago with Professor Eric
Miller, who wrote this book on how to integrate all this stuff in an iterative
way...
[https://link.springer.com/article/10.1007/s11067-005-2630-5](https://link.springer.com/article/10.1007/s11067-005-2630-5)

------
massysett
Ironically this article exposes the fallacy of “induced demand.” Proponents of
this mindset, such as the author of this article, claim that more lanes
inevitably lead to more traffic. But the article leads off with an example of
a massive highway expansion project that is a “boondoggle” because traffic
fell and the lanes are empty. I thought that lanes automatically fill up,
because induced demand.

~~~
nimbleal
Surely, unless the claim was that in all cases, everywhere a new road means
new levels of traffic to fill it, a single counterexample does nothing to
expose a fallacy? I feel like your “inevitably” here is a bit strawman-y

------
sradman
> population and land-use patterns... are two of the most important variables
> in any TDM [Travel Demand Model]

All models are based on assumptions. Revisiting those assumptions should be a
continuous process that forms a tight feedback loop, especially given the long
timelines and large capital costs involved with civil infrastructure projects.

If population and land-use assumptions are the key factors then the important
questions should be how these assumptions will be validated and how often.
These questions seem to be missing from the article.

------
mehrdadn
Some more reading:
[https://en.wikipedia.org/wiki/Induced_demand](https://en.wikipedia.org/wiki/Induced_demand)

> City planner Jeff Speck has called induced demand "the great intellectual
> black hole in city planning, the one professional certainty that everyone
> thoughtful seems to acknowledge, yet almost no one is willing to act upon."

~~~
mattmcknight
That's bizarre, because I see it as the most overused argument over the past
25 years! People oppose any lane additions with induced demand.

------
thehappypm
Public transportation should really just be bus-based. Every city that has a
large public transit system — worldwide - spends an absolute fortune on
trains, track maintenance, overhead lines, operators, and so on. Even shiny
European systems are hugely hugely expensive. They often use a wide variety of
approaches — Boston for example has about a half dozen completely incompatible
rolling stock. Buses can be deployed and scaled cheaply, routes can adapt
quickly, dedicated bus lanes can be built with paint and not tunnels. Choke
points can use dedicated right-of-way and electric infrastructure can go into
tunnels with far less ventilation need. Buses can handle a fallen tree by
driving around it. Buses don’t need special tracks to take them to depots. A
down bus doesn’t back up the buses behind it. The list goes on and on.

~~~
currymj
do you have any thoughts on what causes these systems to stick to trains?

to me, as a user of public transit, they just seem somehow more pleasant, in a
way I can't really make sense of. I strongly dislike riding in buses and try
to avoid it, whether part of transit systems, Greyhound/Peter Pan, or even
high-end charter buses.

maybe if you had electric (no exhaust, quiet) buses with frequent reliable
service, dedicated lanes almost everywhere, nice bus stops without hostile
architecture, I wouldn't feel such a strong preference, but I'm not sure.

I'm wondering whether it's not just that I subconsciously dislike getting
jostled around and feeling slightly carsick.

~~~
vonuebelgarten
> do you have any thoughts on what causes these systems to stick to trains?

Trains are excellent for dense urban environments and better yet when
integrated with another modes. I take Berlin as an example: You have fare
zones and S/U-Bahn everywhere in the city center extending for to Potsdam,
etc., trams in the former east, buses on the less dense parts of the city.
Also trivial access to regional and long-distance trains. And it also
disproves the typical excuse "You can't do that in an old city": some U-Bahn
lines exists since 1902, the city got devastated by war and then there was the
DDR. The reunification needed a lot of work and yet the system survived. Took
me a long time to notice there was no Ubers, maybe because it was not that
advantageous for people to use it and Uber Inc. just gave up instead of
fighting city regulations, as they did everywhere).

I compare with the systems from my native Brazil, where public transportation
ranges from pathetic inefficient on big cities to non-existent in small towns.
Hell, I really miss Berlin.

~~~
thehappypm
My point is that most cities are not Berlin, which is one of the wealthiest
cities in one of the wealthiest countries on Earth. What does Cleveland have
to learn from Berlin?

------
renewiltord
These big projects aren't about actually solving problems. They're a
combination of public works projects and returning money to your political
investors. So you choose the project then construct the justification. Because
the true confidence interval is really large, you can go either way.

If you're good about it, you can drag the project out with delays but with
milestones you can talk about politically.

Then by the time the project has been discovered to have been unnecessary
you're out of power and it's no longer a problem.

And your investors have a good return to invest in the next guy to give them
the next project.

~~~
sthnblllII
I think a lot of Americans are still in the world war 2 generation mindset
about the US being corruption-free. The truth is that corruption at every
level has gotten steadily worse throughout the last century, but the culture
hasn’t yet changed to be vigilant of it, probably because most Americans are
very honest themselves.

~~~
renewiltord
I think that's it, honestly. I think this relatively high-trust culture that
Americans have actually makes the society pretty efficient and it's much more
pleasant to live in.

But it has none of the anti-bodies to the kind of cynical corruption that many
other countries find endemic. And so when it came here, America had no
defence. Because the host is still so healthy, it still doesn't realize it is
carrying this parasite.

It'll be interesting to see what happens when the host becomes unhealthy.

------
brundolf
This kind of complex-system-optimization problem seems ripe for improvement
via machine-learning. Cases where 1) precisely modeling the outcome is totally
intractable, and 2) you really just need to get "close enough" to get good
results. It also helps that this case is predictive in nature (so it's easy to
go back and measure accuracy) and has an enormous set of available training
data (all traffic happening everywhere across the country).

It feels very similar in spirit to that story about Google reducing data
center energy use by 40% via ML optimization:
[https://deepmind.com/blog/article/deepmind-ai-reduces-
google...](https://deepmind.com/blog/article/deepmind-ai-reduces-google-data-
centre-cooling-bill-40)

More broadly I've started wondering if there's a huge opportunity to apply
software to civil improvement. Everything from detecting patterns of
corruption, to aggregating data that can inform voters, to identifying sources
of inefficient spending. I don't put much stock in things like digital
voting/governance, but in the area of "data crunching and presentation" I
think there's a lot that could be done.

~~~
nicolaskruchten
> an enormous set of available training data (all traffic happening everywhere
> across the country).

I'm not sure this is very helpful to predict traffic patterns over the next
20-30 years in a policy-sensitive way... All the historical data in the world
wouldn't have predicted the rise of Uber, the pandemic, the maybe-eventual
rise of self-driving cars etc.

~~~
brundolf
True, but it doesn't sound like the approach described in the article factors
in extraordinary circumstances like that either

~~~
nicolaskruchten
The model won't tell you how likely these scenarios are, but one advantage of
this class of model over black-box ML function-fitting is that you can do
scenario planning. You can do models runs like "what happens if the price of
oil shoots way up?" or "what happens if 50% of the cars are taxis?" (e.g.
Uber-driven future) or "what happens if transit all of a sudden gains a huge
perceived cost?" (e.g. respiratory-virus pandemic) in the third and fourth
stages of the model. In the early stages of the model you can look at stuff
like "what happens if firms abandon city centers?" or "what happens if 50% of
white-collar work is done from home?" etc.

------
sideshowb
Pre 2000s transport planning is a textbook study of optimizing for the wrong
thing. Although it failed to reduce congestion you could argue the extra trips
contributed to GDP... but that's subject to the same problem...

Ultimately what is the correct metric though? Well being?
[https://www.mdpi.com/2071-1050/12/8/3180/htm#](https://www.mdpi.com/2071-1050/12/8/3180/htm#)

------
DoreenMichele
The interstate system dates to 1956.[1] So it is part of the set of mental
models that haunt the US and continue to poison our built environment. The
post-WWII era is the same era that gave birth to the modern suburb and the
Baby Boom, giving us the Baby Boomers.

Americans have been basically brainwashed into thinking that patterns of
development from that era are right and good and so forth and then we put
those models on steroids and do more of that same.

Our suburbs began as houses of around 1200 sq. ft. Last I saw stats, the
average new home in the US was over 2400 sq. ft. (though a recent private
conversation with a professional urban planner suggests those figures may
finally be dropping).

We need an entirely new set of mental models, something I think of as "the
butterfly economy" based on a comment I made on HN once.[2]

There is a potential path forward, but we aren't going to take it because that
would involve listening to a woman and this will not happen. This is a hill
our current world is eager to die upon, so we will remain haunted by the
ghosts of Christmas past -- prisoners of mental models that served our parents
and grandparents extremely well, so they got burned into our collective psyche
as the only good way to do anything and never mind that the world has changed
and all of that is very much out of date.

I'm short of sleep, tired of getting zero respect, underfed (as is the norm
late in the month), in a generally bad mood over how my crappy existence
remains crappy largely due to sexist BS and no amount of pointing out the
sexist BS causes it to really budge. So I think that's all I'm going to say
here since I fully expect to get kicked in the teeth for saying anything and
I've had quite enough abuse for one life.

[1]
[https://www.fhwa.dot.gov/interstate/interstatemyths.cfm](https://www.fhwa.dot.gov/interstate/interstatemyths.cfm)

[2]
[https://news.ycombinator.com/item?id=22028732](https://news.ycombinator.com/item?id=22028732)

------
rmrfrmrf
Not shocking at all that Vice would frame an algorithm designed to create
construction jobs via federal funding as "broken" and "poisonous".

------
aaron695
The article actually begrudgingly admits the model works fine. It's nice they
are honest for a change, normally they just factoid it away.

And concludes it's politics.

Not sure if I read the same article as everyone else?

------
ArkVark
Hub and spoke public transport is dead. It relies on huge infrastructure
investment and open access.

The future is autonomous minibusses with algorithmically-derived live routes,
served on a subscription basis by private companies to private individuals.
This way people of similar socioeconomic status can rub shoulders with
eachother and feel more comfortable, and receive a greater standard of
service.

It might very well be necessary to modify roads and road rules to facilitate
autonomous vehicles - that's the kind of public investment we should be
making.

~~~
kolinko
The issue with private services is that they will handle most profitable
routes and ignore less profitable ones.

You end up with a system where there is even more socioeconomic exclusion
(poorer people living in areas where they need to use cars, but cars are more
expensive and won’t get into the future cities).

Or - at worst - it won’t work at all, because you will need a car anyway for
those 5-10% long tail destinations that private transport won’t cover.

I think this is the reason European countries have public transportation -
which is forced to tackle less profitable routes, but can earn back money on
the profitable ones. (Similarly post office)

~~~
coryrc
Hope does that compare with the reality of jitneys both in India and the
similar phaenoma around NYC providing timely transportation for the working
class? (In NYC often persecuted by the government as well)

------
throwawaysea
This article repeats a common flaw, which is citing the theory of “induced
demand”. This is merely rhetorical framing. Demand isn’t induced, but
fulfilled. And it is a good thing, because that’s what those drivers want - to
make their trips easily, which is what road infrastructure enables.

The notion that increased road infrastructure will magically hold congestion
steady or worsen it is laughable. It just means demand hasn’t been satisfied
yet. Clearly a 1000 lane highway would not be congested, so there is some
finite and lower number where demand balances out with supply. This is no
different than supply and demand in any other situation, which is why the
label of “induced demand” is without meaning and simply a rhetorical device.

~~~
sideshowb
This isn't physics and it isn't an exact equilibrium, but within the range of
highway sizes we actually have (not your 1000 lane hypothetical) it seems to
hold. Not only do people drive more, but more origins and destinations get
_built_ to take advantage of new transport links.

~~~
iso947
A 1000 line highway would take tens of minutes, maybe upto an hour, to drive
to the outside lane, it would have its own interesting traffic problems.

~~~
TeMPOraL
I can imagine you'd want to split it e.g. into 250 4-lane tracks, with the
leftmost track being reserved for people going all the way to the end of the
highway, rightmost track for people who're about to exit the highway, and the
middle tracks for people traveling to various points along the highway path,
sorted left-to-right by distance, descending.

Otherwise it would be just one huge mess.

