From Keith Hennessey:
Geographic politics distorts and often dominates government investment in physical infrastructure. Highway funds and airport funds especially are allocated in part based on which Members of Congress have maximum procedural leverage over the spending bill. Even if you could somehow get Congress to stop earmarking infrastructure spending (good luck), and even if you could rely on the Executive Branch not to allow their own political goals to influence how they allocate funds, local geographic politics would come into play at the state level, since much federal infrastructure spending flows through State governments. This is where reality most falls short of a valid theoretical starting point for increasing productivity and long-term growth.
Keith argues that infrastructure spending isn't useless but it does face a lot of problems that prevent it from quickly creating jobs. It's not a great "investment in America".