The interstate system was designed to mimic the German Autobahn except for one important thing. The Autobahn doesn't rip through city centers. There are well designed ring roads to disperse traffic into cities. Just take a look at a map of any German city and see how the highways all go around the cities.

Edit: there are actually two other important differences, one being the construction quality of the roadbed which is basically garbage in the US. The other is the avoidance of long straightaways. Even in flat open country, there are curves engineered into the Autobahn which helps keep drivers alert.