
The Design of the US Interstate Highway System (1944) [pdf] - putzdown
https://www.enotrans.org/wp-content/uploads/membersOnly-1944-Interregional-Highways.pdf
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austincheney
I35 runs from Mexico to Canada, of which one third is in Texas (just over 500
miles). I35 is unique for being the only interstate road to split into
multiple directions without designation as a loop or spur. This uniqueness
occurs not once, but twice:

* [https://en.wikipedia.org/wiki/Interstate_35E_(Texas)](https://en.wikipedia.org/wiki/Interstate_35E_\(Texas\))

* [https://en.wikipedia.org/wiki/Interstate_35W_(Texas)](https://en.wikipedia.org/wiki/Interstate_35W_\(Texas\))

* [https://en.wikipedia.org/wiki/Interstate_35E_(Minnesota)](https://en.wikipedia.org/wiki/Interstate_35E_\(Minnesota\))

* [https://en.wikipedia.org/wiki/Interstate_35W_(Minnesota)](https://en.wikipedia.org/wiki/Interstate_35W_\(Minnesota\))

~~~
dbcurtis
At one point in time or another I have been on the entire length of I-35 from
Duluth to Corpus Christi. Not as a mission, just happenstance over the course
of years. Probably not on all the side loops, though. I don’t have a point. It
is just interesting to think about one’s travels in terms of line coverage.

~~~
dreamcompiler
I-35 doesn't go to Corpus Christi. Perhaps you branched onto I-37 at San
Antonio?

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jcrawfordor
The interstate highway system was an extremely ambitious and forward-looking
plan. This forward-looking component was not always an easy sell. I regularly
drive one of the last sections of the original interstate system to be
completed, I-25 between Socorro and Truth or Consequences. The existing US
Highways serving this area received very little traffic and work on the
interstate did not even begin until the late '60s, due to a combination of the
state refusing to expend the money and controversy over the bypass issue.

The bypass issue is an extremely important part of the interstate system.
Because interstates must be freeways, it was extremely difficult to place them
through towns, and so they usually "bypassed" the town. Especially in the west
this had a devastating economic impact and lead to a broad trend of urban
blight on roads which are former US highways. Late in interstate construction
efforts were made to prevent this, but the problem was more or less
intractable as not bypassing required a large amount of demolition.

At the same time, in urban areas there was an almost incredible enthusiasm for
freeways. Modern Albuquerque has two freeways which more or less divide it
into four quadrants. However, controversy around routing of I-40 during
initial planning lead to a response of ¿porque no los dos? and at the peak of
freeway mania plans included three east-west cross-town freeways (two of them
barely more than a mile apart) as well as a beltway. Fortunately these plans
were largely abandoned before construction, which is not the case in other
cities in which construction was started before cancellation (for example,
Portland's "Mt. Hood Freeway," one of the many urban freeway projects designed
by Robert Moses who started out hero and ended up villain as the destructive
impacts of urban freeways became clear.

Freeways are, as many large things, an epic history to themselves.

~~~
jcrawfordor
Also, it's impossible to talk about freeways without mentioning I-19, which is
signed in kilometers because it seemed at the time like the US was ready to go
metric, and the Bay Area's I-380 which is not quite two miles long. It would
have been longer had the original plans not been cancelled, but not much
longer. Even then it's longer than I-180 which is only one mile, but I like
the example if I-380 more because it's so heavily trafficked and it's quite
clear at the interchange with I-280 where it almost went on further.

I-19's metric signage and I-280 connect to an odd common thread, though:
California, perhaps because of its size and historic isolation, has
historically had its own way of doing things. This extends to freeways, where
California retained its historic system of marking highways (post-miles)
instead of adopting mile-posts as the federal government dictated. The
difference there is slight, but there's a bigger difference: California did
not, initially, number its exits. Instead they were known only by name. By the
'80s they had started numbering all exits but in areas with older
infrastructure, such as 101 through San Francisco, most exist are still
unnumbered until something forces them to replace the signs. The decision not
to number exits is perhaps partially because of the post-mile system in which
mile numbers are somewhat less linear than mileposts, but probably more due to
California's large set of US Highways which were upgraded to freeway condition
(such as 101) and had not historically been numbered. Today this would be
unusual, a US Highway updated to freeway infrastructure is more often
designated as a freeway (see this happening with US-93 near Las Vegas becoming
I-11), but California did it in a number of major places.

The "California Difference" runs deep. Traffic signal controllers in
California are built to a different standard than in the rest of the country,
for example (except a few states that later adopted the California system).
Mostly it's first-mover advantage.

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meddlepal
Ive always found it curious that in Massachusetts I-90 connects directly to
Boston (biggest city) and Springfield (3rd biggest city) but bypasses
Worcester (2nd biggest city) on its way to Springfield.

The legend is the powerful Worcester industrialists at the time lobbied to
have the road run south of the city so workers wouldn't be able to leave for
the suburbs as easily. Not sure if that's true, but that's the best reason
I've ever been given.

~~~
sib
If I remember correctly (grew up in Connecticut, drove through MA a lot), I-90
does not go directly through Springfield, but, rather, passes by a couple
miles to the north.

~~~
meddlepal
Yea you're right actually. I always forget I-91 is the road that runs between
downtown and the river. Still I-90 is better connected to Springfield that
Worcester... it's only been in the last 15 years or so that Worcester has
gotten good connectivity to I-90 via the 290-146 connector.

~~~
ghaff
I had forgotten about the change in connecting 290 to 90. I was thinking that
it was the same as when I moved into my current house north of Worcester over
20 years ago but I was have forgotten. I probably never took that route enough
for the old connection to register as much of an inconvenience.

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jrockway
Neat. Can someone tell me how they generated all these graphics with 1944
technology? I guess someone just drew everything by hand? (The 3D relief map
of predicted traffic volumes was most intriguing. Looks like early 90s
computer graphics.)

~~~
jcrawfordor
My guess would be that that figure was wireframed by a draftsman using
drafting methods, and then a commercial artist traced it to produce the final
figure. Draftsmen had methods ranging from mechanical drafting arms to
measuring techniques that allowed them to produce very precise figures, and
much of computer graphics, perhaps even to this day, emulates the style
developed by technical artists such as draftsmen and technical illustrators.

Not _too long_ after 1944 these kinds of figures could be produced
automatically by pen plotters and photosetters, but I don't believe anything
of this type was available yet in the '40s. However, as early as the '40s
photosetters and other photographic techniques may have been used in
reproducing these figures more easily than having an engraver produce them in
metal. I don't think this was widespread though, it wasn't until the '60s that
photographic reproduction became common (leading to the term "camera ready"
still used by many journals today for the final draft).

