CLEAN-AIR ACT SIPS, SANCTIONS, AND CONFORMITY

Under the Clean Air Act Amendments (CAAA) the transportation community has been compelled to regard air pollution reduction not merely as on e goal among many but as a crucial constraint on its activities, Nonet heless, to date the actual impacts have been far less than many antici pated in 1990 when Congress enacted the law, States put relatively few transportation control measures into their state implementation plans after assessing emission reduction potential, cost effectiveness, pol itical acceptability, and limits on the flexibility of implementation. While initially the threat of sanctions motivated CAAA compliance, EP A has lost credibility in threatening discretionary sanctions; and man datory sanctions have proved far less certain and timely than the lang uage of the act led many to believe, Of all CAAA provisions, conformit y has had the greatest effect on transportation planning and investmen t, This has been true primarily for complex procedural reasons, howeve r; the regulations appear not to have forced widespread substantive re framing of transportation plans and programs.