ISTEA, the Intermodal Surface Transportation Efficiency Act, passed in 1991, authorized federal funding for highway, transit and safety programs. The funding expired in October 1997, so in March 1998, ISTEA was given an extension. TEA-21, the Transportation Equity Act for the 21st Century ( http://www.fhwa.dot.gov/tea21/ ), which can be viewed as a successor to ISTEA, authorizes a 33% increase in transportation spending. They also include regulations which must be followed to receive federal funding. The next successor, passed in 2005, is SAFETEA-LU, the Safe, Accountable, Flexible, and Efficient Transportation Equity Act: A Legacy For Users, known prior at different times as SAFETEA or TEA-LU ( http://www.fhwa.dot.gov/safetealu/ , http://www.house.gov/transportation/highway/tealu.html , or http://www.house.gov/transportation/highway/increasehighwayfund.html ). A list of corridors is at http://www.aaroads.com/high-priority/ and http://www.fhwa.dot.gov/hep10/nhs/hipricorridors/ .