Truck Weight Uniformity Act of 2011 - Allows a state to authorize a vehicle with a gross weight exceeding certain federal weight limitations to operate on Interstate Highway System routes in the state if: (1) the vehicle is equipped with at least six axles, (2) the weight carried on any single axle does not exceed 20,000 pounds, (3) the weight carried on any tandem axle does not exceed 34,000 pounds, (4) the weight carried on any group of 3 axles does not exceed 51,000 pounds, and (5) the gross weight of the vehicle does not exceed 99,000 pounds.