To amend title 23, United States Code, relating to a vehicle weight and Longer Combination Vehicles exemption for Interstate routes 29 and 129 in Iowa.

Allows vehicles travelling on Interstate 29 between Sioux City, Iowa, and the border between Iowa and South Dakota, as well as those vehicles using Interstate Route 129 between Sioux City, Iowa, and the border between Iowa and Nebraska, to exceed the 80,000 pound weight limit on Interstate Highways. Permits the State of Iowa to allow longer combination vehicles that were not in actual operation on June 1, 1991, to be operated on such routes.