While I think that freeways serve two good purposes -- namely, removing congestion from local roads and allowing cars and trucks to reach their destination more quickly -- I find that the typical implementation of American highways leaves much to be desired. The standard 6-8 lane highway has led to the the segmentation of cities (in addition to the demolition of many neighborhoods). There are a limited number of crossings, many of which are on high-speed arterials. The cloverleafs that connect the arterials to the freeways are dangerous to both cyclists and pedestrians. However, their design can be significantly improved. Japan, for example, is very densely populated, and their real estate is too valuable to sacrifice to a freeway. Most of their inner city highways are four-lane elevated expressways that are constructed along the routes of existing arterials. Local streets that previously crossed the arterial still provide access through. This is a good example. They are ugly, but probably not any uglier than a regular arterial by itself. Also, we wouldn't need as many as Japan due to our lower population density.

Many European cities are building a toll-based tunnelways underground, so as not to disrupt the urban fabric. I'd much prefer underground highways to elevated expressways, but they are more expensive to construct. They would likely have to be paid for in part through tolling.

I think it would be great if we had a sufficient number of easily passable expressways -- either elevated or underground -- that we could afford to lower the speed limit for all in-city surface roads to 25 mph -- the perfect speed for bicycles to integrate into traffic. While bicycles are vehicles, they aren't the same class of vehicle as automobiles. We only integrate well within certain speed limits. The same thing can be said about mopeds, scooters, golf carts, small electrical cars, etc, many of which are not allowed on highways. I am not a fan of bike-specific infrastructure, but speed-specific infrastructure is great.