In 1958, under the auspices of the United Nations, a consortium known as the Economic Commission for Europe was established to standardize vehicle regulations across Europe. Its goals included promoting best practices in vehicle design and equipment and reducing technical barriers to pan-European vehicle trade and traffic. This organization eventually evolved into the
World Forum for Harmonization of Vehicle Regulations, which developed what became the UN Regulations on vehicle design, construction, and safety and emissions performance for vehicles and their components. While many countries adopted or required adherence to the UN Regulations, the United States did not recognize these standards and restricted the importation of vehicles and components not certified by manufacturers as compliant with U.S. regulations. Because of the unavailability in America of certain vehicle models, a
grey market arose in the late 1970s. This provided a method to acquire vehicles not officially offered in the United States, but enough vehicles imported this way were faulty, shoddy, and unsafe that
Mercedes-Benz of North America helped launch a successful
congressional lobbying effort to close down the grey market in 1988. As a result, it was no longer possible to import foreign vehicles into the United States as a personal import, with few exceptions—primarily vehicles meeting Canadian regulations substantially similar to those of the United States, and vehicles imported temporarily for display or research purposes. In practice, the gray market involved a few thousand cars annually, before its virtual elimination in 1988. In 1998, the NHTSA exempted vehicles older than 25 years from the rules it administers, since these are presumed to be collector vehicles. The ongoing ban on newer vehicles considered safe in countries with lower vehicle-related death rates has created a perception that an effect of the NHTSA's regulatory activity is to protect the U.S. market for a modified oligopoly consisting of the three U.S.-based automakers and the American operations of foreign-brand producers. It has been suggested that the impetus for the NHTSA's seeming preoccupation with market control rather than vehicular safety performance is a result of overt market protections such as
tariffs and local-content laws having become politically unpopular due to the increasing popularity of
free trade, thus driving the industry to adopt less visible forms of
trade restrictions in the form of technical regulations different from those outside the United States. An example of the market-control effects of the NHTSA's regulatory protocol is found in the agency's 1974 banning of the
Citroën SM automobile, which some contemporary journalists describe as one of the safest vehicles available at the time. The NHTSA disapproved the SM's designs featuring steerable
headlamps that were not of the
sealed beam design that was then mandatory in the U.S. as well as its
height adjustable suspension, which made compliance with the 1973
bumper requirements cost-prohibitive. The initial bumper regulations were intended to prevent functional damage to a vehicle's safety-related components such as lights and fuel system components when subjected to barrier crash tests at at the front and at the rear. However, these regulations at low-speed collisions did not enhance occupant safety.
Vehicle manufacturers have acknowledged the functional equivalence of the UN and U.S. regulations, encouraged developing countries to recognize and accept both, However, some structural features of the U.S. legal system are incompatible with some aspects of the UN regulatory system. Studies have concluded that commonizing regulations between the US and the rest of the world (which uses
U.N. Regulations) would save significant money, likely without affecting safety. ==Cost and cost-benefit==