[Code of Federal Regulations] [Title 23, Volume 1] [Revised as of April 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 23CFR669.1] [Page 332] TITLE 23--HIGHWAYS CHAPTER I--FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PART 669--ENFORCEMENT OF HEAVY VEHICLE USE TAX--Table of Contents Sec. 669.1 Scope and purpose. To prescribe requirements for certification by the states that evidence of proof of payment is obtained either before vehicles subject to the Federal heavy vehicle use tax are lawfully registered or within 4 months after being lawfully registered if a suspension registration system is implemented.