The Omnibus Trade and Competitiveness Act of 1988 amended the Metric Conversion Act of 1975 to require that each agency of the federal government implement the metric system in its procurement, grants, and other business activities. In December 1991, the Federal Highway Administration (FHWA) established a Metric Work Group to develop an agency policy and conversion plan. The FHWA Conversion Plan is intended to be flexible and has provisions for updating to accommodate new information. The FHWA established a final date of September 30, 1996, for full conversion of the Federal Lands and Federal-aid highway programs. The FHWA and several other federal agencies have adopted the ASTM Manual E380 as the standard for metric conversion.
Based on information obtained from the Construction Metrication Council of the National Institute of Building Sciences in Washington, D.C., and estimated 5% of all products manufactured will have to undergo physical changes. The typical 8x8x16-inch concrete block will change to a slightly smaller 190x190x390 mm. Mortar joints are reduced slightly from « inch to 10 mm. Concrete strength designation will change from psi to megapascals, rounded to the nearest 5 Mpa.