To amend title 23, United States Code, to establish a program for expanding the capacity of heavily-traveled portions of the National System of Interstate and Defense Highways located in urbanized areas with a population of 50,000 or more for the purposes of reducing traffic congestion, improving safety, and increasing the efficiency of the System.

Authorizes the Secretary of Transportation to approve projects within urbanized areas with populations of 50,000 or more for expanding the capacity of open-to-traffic routes on the Interstate Highway System, including construction of noise barriers, acquisition of right-of-ways for future construction of mass transit facilities, and acquisition of land for construction of parking lots.

Sets forth a formula for apportionment of highway funds for such projects.

Specifies: (1) the period of availability of funds apportioned to a State for Interstate System capacity expansion; (2) conditions that must be met in order to use lapsed funds for discretionary projects; and (3) the Federal share (80 percent) of any such expansion projects.

Authorizes appropriations for FY 1993 through 1996.