Section 511(a) of Title 18 makes it a felony knowingly to remove, obliterate, tamper with, or alter an identification number for a road motor vehicle or a road motor vehicle part. Section 511(b) of Title 18 creates exceptions for certain persons who engage in lawful conduct that may result in removal or alteration of an identification number. The legislative history is abundantly clear that subsection (b) is not intended to create a loophole for the operators of "chop shops." See H.R.Rep. No. 1087 on H.R. 6257, 98th Congress, 2d Sess. 23-25 (1984).

Section 511(c) of Title 18 contains the definitions for "identification number," "motor vehicle," "motor vehicle demolisher," and "motor vehicle scrap processor." The term "identification number" means a number or symbol that is inscribed or affixed for purposes of identification under chapter 301 and Part C of subtitle VI of Title 49.

Title 49, Chapter 301 authorizes the Secretary of Transportation to promulgate motor vehicle safety standards. Pursuant to this authority, Federal Motor Vehicle Safety Standard No. 115-Vehicle Identification Number (49 C.F.R. §§ 571.115 and 565.1 to 565.5) requires public VIN numbers on road vehicles (passenger cars, multipurpose passenger vehicles, trucks, buses, trailers, and motorcycles). Part C of subtitle VI of Title 49 (49 U.S.C. § 33101 et seq.) authorizes the Secretary of Transportation to promulgate theft prevention (parts marking) standards. The parts marking regulations are set forth in 49 C.F.R. Part 541. The mandatory component identification requirement applies to certain high theft passenger car lines starting with model year 1987. In 1995, the theft prevention (parts marking) standard was expanded to include certain multipurpose passenger vehicles and certain non high theft lines beginning with model year 1997.