[Code of Federal Regulations] [Title 49, Volume 5] [Revised as of October 1, 2005] From the U.S. Government Printing Office via GPO Access [CITE: 49CFR325.27] [Page 11] TITLE 49--TRANSPORTATION DEPARTMENT OF TRANSPORTATION PART 325_COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS --Table of Contents Subpart C_Instrumentation Sec. 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.