Based on Wikipedia stats on roadway length and population, Germany simply has much less pavement to maintain, on a per-capita basis. Considering roadway length as a whole, the U.S. has 2 1/2 times as much (OK, the factor is 2.57 to be precise), and considering highways only, 1.5 times as much, and that’s not even taking into account that, for a given length of roadway, the typical U.S. street has more and wider lanes. That’s a huge difference, and means that it’s far more costly for the US to maintain its roads.
Why? German is a far more dense country, without anything comparable to the American West with vast scantly populated areas. Plus, within cities, the density is much greater, as single-family homes are rare and past history and current zoning mean that most people live in multistory apartment buildings — all of which means that the footprint of any given city is much, much smaller than a similarly-sized American city, which also means, in turn, that mass transit is, quite simply, substantially more viable, as it requires, not just political will, but a significantly greater level of density than most Americans consider acceptable. And this also means that the roads themselves, even major crosstown arteries, generally have fewer lanes, so there’s less total paved surface per kilometer.
Pavement
Why? German is a far more dense country, without anything comparable to the American West with vast scantly populated areas. Plus, within cities, the density is much greater, as single-family homes are rare and past history and current zoning mean that most people live in multistory apartment buildings — all of which means that the footprint of any given city is much, much smaller than a similarly-sized American city, which also means, in turn, that mass transit is, quite simply, substantially more viable, as it requires, not just political will, but a significantly greater level of density than most Americans consider acceptable. And this also means that the roads themselves, even major crosstown arteries, generally have fewer lanes, so there’s less total paved surface per kilometer.