
Lewis-Mogridge Position - danielam
https://en.wikipedia.org/wiki/Lewis%E2%80%93Mogridge_Position
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tbrownaw
I think this is approximately the same as saying that transportation is the
limiting factor in city growth?

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lmm
Yeah. The length of commute that people are willing to tolerate is
approximately constant, so as transport provision increases the number of
people who work in a given city increases, capped by that same commute time.
Given the value of agglomeration effects (there was a recent piece here on how
authors are more productive if they work around others), isn't that what we
want?

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tschwimmer
Intuitively there feels like there should be an upper bound on this axiom. For
example, imagine a highway 1 mile wide with 50 lanes going each way. That's
220 lanes in each direction. Assume dense traffic with each car taking up 25
of lengthwise- space. A 1 mile stretch of this megahighway would have ~60,000
cars on it. At this density, the 101 between SF and San Jose would be able to
accommodate ~2.8 million cars. A quick search reveals that there are only ~2.5
million cars registered in the counties this highway would run through.

So while I don't doubt that this relationship ('traffic increases to fill the
available road space') is true for some conditions, it's not a universal law.
The real question is finding out where it starts to break down. Maybe there is
some merit to building a super wide highway ;)

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whoopdedo
> A quick search reveals that there are only ~2.5 million cars registered in
> the counties this highway would run through.

Actual number of cars should be lower after the highway is built because
construction would require removing houses to make room for it.

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soVeryTired
There's disturbingly little empirical data there for what should be a very
empirical question.

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mrfredward
>traffic expands to meet the available road space

I'm sure this is in many cases true, but there is a danger in mistaking the
metrics for the goals here. If people drive less, it makes the numbers look
better, but people staying at home saying "it's impossible to get anywhere
this time of day" is hardly the mark of an effective transportation system.

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aaronbwebber
Sure but that means your argument for building a new highway needs to be "it
will get more people where they are going" and not "it will reduce
congestion", and you definitely can't pull any "if people are able to get
where they are going faster it will reduce emissions" nonsense, which does get
brought up.

And if the problem you are solving is "get more people where they are going"
all of a sudden highways no longer look like a cost-effective solution at all,
and public transportation looks _a lot_ better. A lot of highway expansion
gets justified by the claim that it will reduce congestion, despite a huge
amount of empirical evidence and theoretical justifications (e.g. TFA) that it
does not.

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hhs
If interested, there was a similar conversation recently about the Downs-
Thomson paradox, noting the relationship between road network improvements and
traffic congestion. It's here:
[https://news.ycombinator.com/item?id=20133027](https://news.ycombinator.com/item?id=20133027).

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cr0sh
Didn't Seattle (or some other major PNW city/area) actually remove or close
roads in their area, and saw that congestion decreased overall? I seem to
recall reading about that several years ago...

EDIT: fixed PSNW -> PNW

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Merrill
This probably depends on:

\- fuel being cheap,

\- time spent driving having a low value,

\- zoning that discourages high-density development, and

\- overhead costs of buying and selling homes high enough to discourage moving
nearer to work.

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sarcasmic
Sometimes it really shows that many early Wikipedia articles were someone's
labor-of-love about a relatively obscure topic, and even today there's uneven
levels of notability across the encyclopedia.

Instead of these hyphenated iron laws of transportation demand that no one has
ever heard of that all say the same thing, the article of "induced demand"
ought to suffice, and these formulations, if they exist original sources at
all, ought to become references in that article's footnotes.

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pjc50
Almost all "deletion for non-notability because I've not heard of it" reasons
should be invalid. Wikipedia deletes far too many people's work in the service
of a small number of core maintainers.

