49 CFR § 554.4 - Office of Vehicle Safety Compliance.
The Office of Vehicle Safety Compliance, investigates compliance with Federal motor vehicle safety standards and associated regulations, and to this end may:
(a) Verify that manufacturers certify compliance with all applicable safety standards;
(b) Collect field reports from all sources;
(c) Inspect manufacturers' certification test data and other supporting evidence, including dealer communications;
(d) Inspect vehicles and equipment already in use or new vehicles and equipment at any stage of the manufacturing, distribution and sales chain;
(e) Conduct selective compliance tests; and
(f) Utilize other means necessary to conduct investigations.