Transportation Equity Act for the 21st Century

The United States federal Transportation Equity Act for the 21st Century (TEA-21) was a federal transportation bill enacted June 9, 1998, as Public Law 105-178. TEA-21 authorized federal surface transportation programs for highways, highway safety, and transit for the 6-year period 1998-2003. Because Congress could not agree on funding levels, the Act, which had continued past 2003 by means of temporary extensions, was allowed to lapse.

The transportation equity act requires that seven planning factors be included in regional transportation plans. The plans must:

Factor 4 was expanded by the Safe, Accountable, Flexible, Efficient Transportation Equity Act (SAFETEA-LU) in 2005 and now reads: "protect and enhance the environment, promote energy conservation, improve the quality of life, and promote consistency between transportation improvements and State and local planned growth and economic development patterns". See 23 USC 135(d)

Section 1211(d) prevents the United States Department of Transportation from requiring state departments of transportation from using the metric system. This has had the effect of delaying metrication in the United States with respect to road construction, though some states had already completely converted.

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