To authorize the use by States of Federal-aid highway funds to relieve congestion or improve air quality.

Authorizes Governors of States containing ozone or carbon monoxide nonattainment areas or areas for which congestion management programs have been adopted to use up to 25 percent of specified Federal aid highway funds for transportation-related projects that would further the goals of congestion programs or improve air quality. Limits the Federal share of a project to 75 percent of the total cost. Lists authorized projects.