Too many too adequately cover here, but let’s start with induced demand. You notice your highway is backed up constantly at rush hour. You figure adding a new lane will help, so you do, and it appears to help at first. What happens over the next year or so is that people who were taking other options now use the highway, and it fills up again. That leads to needing another lane, and at some point, you’ve invented the Katy Freeway.

Or how about that we’re subsidizing the trucking industry with our taxes? The wear and tear on our roads goes up exponentially with weight–not by a square factor, not by a cube factor, but by the fourth power. There is no way that the additional amount trucks pay in taxes can be covering that. These trucks could be largely replaced by a better freight rail network (we already have a pretty good one, just needs to be better), which would be far more fuel efficient per ton of goods.

Or how about that highways encourage urban sprawl, which makes all other infrastructure more expensive. Have to run sewer and electricity to all those far flung neighborhoods. Your taxes are higher because of this. Not only that, but the neighborhoods that are subsidizing other neighborhoods might not be what you think (I linked to the pertinent point around the 5 minute mark, but the whole video is worth a watch on this subject) (and the whole channel, for that matter).