Labeling Automobile Parts to Combat Theft
Finn, Peter, The FBI Law Enforcement Bulletin
Motor vehicle theft represents a major problem in the United States. In 1995, motor vehicle  owners reported nearly 1.5 million thefts representing 1 out of every 139 vehicles in the country.  The theft of parts from vehicles poses an even more common problem, outnumbering vehicle theft 5 to 1. 
In the 1950s and 1960s, young adults stole cars, drove them for a short period of time, and then abandoned them, resulting in very high vehicle recovery rates. In fact, in many smaller and rural jurisdictions, joyriding remains the predominant reason for car thefts. However, beginning in the 1970s, substantial numbers of thieves in larger cities started stealing cars for profit, resulting in fewer recovered cars and more parts missing from those recovered. Car thefts increased because of a proliferation of "chop shops," which sell stolen parts either directly to consumers or to automobile dealerships or repair shops for resale to customers.
During this period, thieves began to employ numerous clever schemes that remain in use today. For example, thieves steal, strip, and abandon a car, and the innocent owner reports it stolen. The police eventually recover the car and cancel the theft record. The thieves then purchase the frame at an insurance or police auction, reattach the stolen parts, and sell the vehicle. Vehicle owners use this same technique, stripping their own cars, removing enough parts for their insurance companies to declare a total loss, then filing a claim for reimbursement.
In another commonly used scam, car thieves buy a salvaged car for its title and vehicle identification number (VIN). Stealing the same model car, they place the VIN from the salvaged car onto the stolen car, which they sell to an unwitting buyer. These examples represent a small number of the various techniques car thieves use. Law enforcement must make the most of new strategies developed to combat these innovative car thieves.
FEDERAL PARTS-MARKING LEGISLATION
Until recently, automobile theft investigators, in an attempt to cope with these types of theft schemes, often had no means of identifying which vehicles the parts came from, if the parts were stolen, or whether a VIN actually belonged to the car on which investigators found it. As a result, Congress enacted the Motor Vehicle Theft Law Enforcement Act of 1984, which directed the U.S. Department of Transportation (DOT) to develop a vehicle theft prevention standard mandating that automobile manufacturers inscribe or affix an identifying number or symbol onto certain parts of passenger cars that the DOT deemed a high theft risk. 
Manufacturers designed anti-theft labels  to trace automobile parts to the original vehicle in order to help prove that they were stolen. In addition, because the federal government and many states made it a criminal offense to remove or tamper with the labels, law enforcement investigators may seize and confiscate parts with defaced or missing labels. In some states, officers also may arrest individuals in possession of cars or parts with missing labels.
In 1992, Congress enacted the Federal Anti-Car Theft Act, directing DOT to require that manufacturers mark an additional 50 percent of their remaining automobile models by December 1994 regardless of the vehicle's theft rate. This act further required that the U.S. Department of Justice (DOJ) assess the effectiveness of the parts marking by 1997, and, if parts marking was found to inhibit chop-shop operations and deter motor vehicle theft, extend parts marking to all remaining vehicle lines by December 1997.
In response to this mandate, the National Institute of Justice commissioned a study to determine whether antitheft labels have substantially reduced automobile thefts. One part of the evaluation examines the National Highway Traffic Safety Administration data on automobile theft rates based on information from the FBI's National Crime Information Center and the DOT's insurer database. …