CFR > Title 49 - Transportation > SUBTITLE B—Other Regulations Relating to Transportation > CHAPTER III—FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (Parts 300–399) > SUBCHAPTER A—GENERAL REGULATIONS (Parts 300–325) > PART 325—COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS > SUBPART C—Instrumentation (§325.21 to §325.27) > 325.27—Use of a windscreen.

325.27—Use of a windscreen.

A properly installed windscreen, of the type recommended by the manufacturer of the Sound Level Measurement System, shall be used during the time that noise emission measurements are being taken.