Governments don't build roads in America. They never have. They fund roads and maintaince via taxation, but there are other ways to fund roads if need be. The roads are built and maintained by construction contractors, and governments (at most) function as management.
Wrong.
1 ) The government decides to build roads (except in the case of a new tract under development by a developer).
2 ) The government sets up a planning commission which involves public and private planning firms.
3 ) The government decides on a plan, involving many government organizations, ranging from the ESA, the EPA, city councils, and so on.
4 ) The government contracts various firms to do the actual surveying, grading and paving.
5 ) Some government agency (state transportation agency, etc., depending on jurisdiction) oversees the project to completion.
6 ) Some government agency (state transportation agency, etc., depending on jurisdiction) maintains the completed road, installs signs, etc.
7 ) Sometimes, that government agency hires outside contractors to engage in significant repairs or improvements.
8 ) Utility companies are allowed, as per agreements with the government, to do installation and maintenance on their utilities which lie underneath the road or alongside it.