If you look at something where you can compare prices between countries, like per-mile subway construction costs, the U.S. is a huge outlier, with procurement costs much higher than Europe.
The higher-than-Europe comparison I had not heard before. The higher than private industry cost of United States government contracting (and contracting by local units of government when they spend federal funds) is dictated by the Davis-Bacon Act,
http://www.dol.gov/whd/govcontracts/dbra.htm
once we understand that the law's requirement to pay "prevailing wages" means, in that context, to hire union labor even when less expensive nonunion labor is available.