[xxpor]

>Seattle's mass transportation system has no impact on Miami's

This is only true if you look at it in the absolute shallowest way. Seattle's increased output due to its subway system helps the entire country.

95% (to pull a number out of my rear end) of the use of interstates in a city are for private vehicles belonging to city residents. I-5 in Seattle doesn't "help" Miami either.

[bhupy]

You can apply this thinking to the entire world, then. We ought to all be a part of one global country, and London's increased output helps us all!

If only cooperation and decision-making were so simple.

[Brendinooo]

>95%...of the use of interstates in a city are for private vehicles belonging to city residents

This is probably nowhere close to true. People living in cities have less reason to use it. Interstates near and through cities benefit the broader region economically through commuters.

But the bulk of the miles of the interstate system are the boring stretches through Wyoming or wherever, and those stretches tie the nation together economically. Half of all big truck miles are on the Interstate, according to some totally random website I found.