Like paytonc, I earn my living in this area (although my personal specialty is more in the software for regulatory compliance and investment analysis areas), and in fact we work for sometimes competing and sometimes collaborating firms.

You might be interested to read the following, especially the transit portions, to understand how infrastructure condition and performance makes its way into the Federal process:
http://wwwcf.fhwa.dot.gov/policy/2006cpr/index.htm