This part prescribes the requirements necessary to implement 23 U.S.C. 163, which encourages States to enact and enforce 0.08 BAC per se laws through the use of incentive grants and Section 351 of Public Law 106-346--Appendix, which requires the withholding of Federal-aid highway funds from any State that has not enacted and is not enforcing a 0.08 BAC per se law as described in 23 U.S.C. 163.