[toddmorey]

You may hear the first argument from me, though it's not mine. The Interstate Highway in America was modelled after the Autobahn in Germany. But we made two dramatic changes: (1) we put the highways right through cities instead of alongside them, and (2) we cut through the landscape rather than adhering to it (so our roads could be straight instead of winding).

There have been a few unintended consequences of those decisions. First, the highways literally divided cities like walls, cutting neighborhood access off from one community to another. I live close enough to my downtown to walk, but to do so, I'd have to cross a highway.

Second, there's some consensus among researchers that the long, straight stretches of highway contribute to driver fatigue in a way that a more active driving experience (from the occasional turns) does not.

While the autobahn curves with the landscape, it's not as dangerous as a country road. And by not dissecting the cities, it makes life in the city more efficient and connected.

[Spooky23]

Note that it wasn't always an unintended consequence. When Robert Moses built the expressway and parkway systems in NYC, he expressly targeted black and puerto rican neighborhoods to bear the brunt of the impact. On Long Island, his bulldozers sliced small farms in two, but avoided the great estates of the mega rich -- at huge expense to both taxpayers and generations of commuters.

[rcourtie]

This is anecdotal, but I can see this highway dividing towns pretty starkly in Menlo Park. The town is divided East/West by US-101. The difference between West Menlo Park and East Menlo Park is stark, West is filled with incredibly wealthy, white people whereas the East is filled with much poorer, mostly latino and black people.

[koenigdavidmj]

I-5 is sort of interesting in Seattle. It cut the city in half, and was essentially built right through the middle of a lot of developed areas. Before it was put in, you could walk from First Hill to Downtown, but then they dropped a highway down the middle and had only a couple of roads cross it. It wasn't until recently that walking from First Hill to downtown could require a mile or two of extra walking to get to one of the streets that crossed the highway.