info for hellovit Wrote:
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> There are specific designations for federal
> highways based on position direction and what they
> do. Odd number north south. Even east and west.
> 2xx 1xx eg 195 295 are bypasses that travel on the
> edge of a metropolitan area.3xx 5xx are highways
> that terminate in the city.eg 395 595. 4Xx 6xx 8xx
> are beltway's that circle and never enter the
> city. The further south the lower the number. The
> number is bigger if it is further north. Both
> coast eg California and Maryland for example start
> with route 1 and increase as you head towards the
> Mississippi. If you look at the highway number and
> mile marker, you can determine where you are going
> using this system. This was and is all set by an
> organization called the strategic highway defense
> initiative started by president Eisenhower in the
> 1950s and yes, he was inspired by the German
> system because it worked so well. I95 is also kept
> a certain distance from the ocean to keep it safe
> from ship to shore bombardment. It also determined
> thickness of the road and height of the bridges to
> accommodate military equipment. Lastly, for every
> tax dollar used for the highway the government has
> reaped trillions in return in growth and tax
> revenue. Oh that's right, wasn't Eisenhower a
> republican? Imagine that.
Close, but the numbers rise consistently going west to east in the Interstate system; the U.S. Route system is the one that starts low in the east (US1) and goes higher as you go west (US101). And when it comes to three-digit Interstates, odd first digit = spur, even = loop.
There are exceptions -- I-99 should not be I-99, as it's in the wrong place; I-270 should have an odd first digit. Some of those are historical, due to changed plans; others are just weird (I-99 was some sort of political hack).
See
https://en.wikipedia.org/wiki/Interstate_Highway_System and especially
https://en.wikipedia.org/wiki/Interstate_Highway_System#Auxiliary_.28three-digit.29_Interstates_.28contiguous_U.S..29
Oh, and the leading digit thing is why there can be multiple I-595s, perhaps even in the same state, although for obvious reasons I'm sure states try to avoid it.
Fun stuff!