Why was the proposed wind farm not built off the coast of Cape Cod? It was stopped by "environmentalists". Why don't we have high speed rail up and down the northeast corridor? "Environmentalists" won't allow it. Of course the real environmentalists support Cape Cod wind farms and high speed rail. But people who worry that these projects with spoil the view from their expensive homes can use environmental regulations to stop the projects.
That's right -- taking a modest amount of space away from gasoline-burning cars and giving it to bicycles requires a one- or two-year environmental review process.
There are a lot of ins and outs about why that is exactly, but at a high level the issue is that environmental impact review requirements were written with the general spirit of "Let's worry about someone proposing to do something bad." Yet it turns out the exact same process that makes it cumbersome to do something bad also makes it cumbersome to do something good. And at a time when status quo transportation infrastructure is heavily tilted toward moving private automobiles and filling them with gasoline, that bias toward inaction can be very environmentally destructive.
In an earlier post entitled "Machete" I quoted from a trailer for the film of the same name:
If you hire him to take out the bad guys, make sure the bad guys aren't you!