23130. (a) No person shall operate either a motor vehicle or combination of vehicles of a type subject to registration at any time or under any condition of grade, load, acceleration, or deceleration in such a manner as to exceed the following noise limit for the category of motor vehicle within the speed limits specified in this section: Speed limit Speed limit of 35 mph of more than or less 35 mph (1) Any motor vehicle with a manufacturer's gross vehicle weight rating of more than 10,000 pounds and any combination of vehicles towed by such motor vehicle ........... 86 dbA 90 dbA Speed limit Speed limit of 45 mph of more than or less 45 mph (2) Any motorcycle other than a motor-driven cycle .............. 82 dbA 86 dbA (3) Any other motor vehicle and any combination of vehicles towed by such motor vehicle ..... 76 dbA 82 dbA (b) The noise limits established by this section shall be based on a distance of 50 feet from the center of the lane of travel within the speed limit specified in this section. The Department of the California Highway Patrol may provide for measuring at distances other than 50 feet from the center of the lane of travel. In such a case, the measurement shall be corrected so as to provide for measurements equivalent to the noise limit established by this section measured at 50 feet. (c) The department shall adopt regulations establishing the test procedures and instrumentation to be utilized. These procedures shall allow, to the extent feasible, noise measurement and enforcement action to be accomplished in reasonably confined areas such as residential areas of urban cities. (d) This section applies to the total noise from a vehicle or combination of vehicles and shall not be construed as limiting or precluding the enforcement of any other provisions of this code relating to motor vehicle exhaust noise. (e) For the purpose of this section, a motortruck, truck tractor, or bus that is not equipped with an identification plate or marking bearing the manufacturer's name and manufacturer's gross vehicle weight rating shall be considered as having a manufacturer's gross vehicle weight rating of more than 10,000 pounds if the unladen weight is more than 5,000 pounds. (f) No person shall have a cause of action relating to the provisions of this section against a manufacturer of a vehicle or a component part thereof on a theory based upon breach of express or implied warranty unless it is alleged and proved that such manufacturer did not comply with noise limit standards of the Vehicle Code applicable to manufacturers and in effect at the time such vehicle or component part was first sold for purposes other than resale. 23130.5. (a) Notwithstanding the provisions of subdivision (a) of Section 23130, the noise limits, within a speed zone of 35 miles per hour or less on level streets, or streets with a grade not exceeding plus or minus 1 percent, for the following categories of motor vehicles, or combinations of vehicles, which are subject to registration, shall be: (1) Any motor vehicle with a manufacturer's gross vehicle weight rating of 6,000 pounds or more and any combination of vehicles towed by such motor vehicle ........................................... 82 dbA (2) Any motorcycle other than a motor-driven cycle .... 77 dbA (3) Any other motor vehicle and any combination of vehicles towed by such motor vehicle .............. 74 dbA No person shall operate such a motor vehicle or combination of vehicles in such a manner as to exceed the noise limits specified in this section. The provisions of subdivisions (c), (d), (e), and (f) of Section 23130 shall apply to this section. (b) Measurements shall not be made within 200 feet of any intersection controlled by an official traffic control device, or within 200 feet of the beginning or end of any grade in excess of plus or minus 1 percent. Measurements shall be made when it is reasonable to assume that the vehicle flow is at a constant rate of speed, and measurement shall not be made under congested traffic conditions which require noticeable acceleration or deceleration. (c) Test procedures and instrumentation to be utilized shall be in accordance with regulations of the Department of the California Highway Patrol, except that measurement shall not be conducted within 200 feet of any intersection controlled by an official traffic control device, or within 200 feet of the beginning or end of a grade. (d) The noise limits established by this section shall be based on a distance of 50 feet from the center of the lane of travel within the speed limit specified in this section. The Department of the California Highway Patrol may provide for measuring at distances closer than 50 feet from the center of the lane of travel. In such a case, the measuring devices shall be so calibrated as to provide for measurements equivalent to the noise limit established by this section measured at 50 feet. Vehicles equipped with at least two snowtread tires are exempt from this section. 23135. It is unlawful for any person to operate upon a highway any vehicle which was originally manufactured as a motorized bicycle, as defined in Section 406, and which has been modified in such a manner that it no longer conforms to the definition of a motorized bicycle. 27150. (a) Every motor vehicle subject to registration shall at all times be equipped with an adequate muffler in constant operation and properly maintained to prevent any excessive or unusual noise, and no muffler or exhaust system shall be equipped with a cutout, bypass, or similar device. (b) Except as provided in Division 16.5 (commencing with Section 38000) with respect to off-highway motor vehicles subject to identification, every passenger vehicle operated off the highways shall at all times be equipped with an adequate muffler in constant operation and properly maintained so as to meet the requirements of Article 2.5 (commencing with Section 27200), and no muffler or exhaust system shall be equipped with a cutout, bypass, or similar device. (c) The provisions of subdivision (b) shall not be applicable to passenger vehicles being operated off the highways in an organized racing or competitive event conducted under the auspices of a recognized sanctioning body or by permit issued by the local governmental authority having jurisdiction. 27150.1. On and after the effective date of regulations and standards adopted by the commissioner pursuant to Section 27150.2, no person engaged in a business which involves the selling of motor vehicle exhaust systems, or parts thereof, including, but not limited to, mufflers, shall offer for sale, sell, or install, a motor vehicle exhaust system, or part thereof, including, but not limited to, a muffler, unless it meets such regulations and standards. A violation of this section shall constitute a misdemeanor. 27150.2. The commissioner shall, after the study required by Section 27150.3, and after public hearings, adopt regulations setting standards for the certification of vehicular exhaust systems based solely upon noise standards consistent with the total vehicle noise levels set by Sections 23130 and 23130.5. Such regulations shall include, but need not be limited to: (a) Provisions for standards for vehicular exhaust systems, based on manufacturers' data and subject to such inspections and other verification as the commissioner may prescribe. (b) Provisions for the licensing of stations to implement the provisions of this section, and Section 27150.1, and for the denial, revocation, or suspension of any license for failure to comply with the provisions of this section or any regulation adopted thereunder. The regulations may provide for the exemption of vehicular exhaust systems where compliance with the regulations would cause an unreasonable hardship without resulting in a sufficient corresponding benefit with respect to noise level control. The regulations adopted pursuant to this section shall become effective one year after the regulations are filed with the Legislature pursuant to Section 27150.4. 27150.3. The commissioner shall conduct a study to determine the best means of implementing the requirements of Section 27150.1. The results of such study shall be filed with the Legislature and made available to the public as soon as practicable but not later than January 5, 1973. 27150.4. The commissioner shall file the regulations adopted pursuant to Section 27150.2 with both houses of the Legislature not later than six months after the study is filed as specified in Section 27150.3. 27150.5. Any person holding a retail seller's permit who sells or installs an exhaust system, or part thereof, including, but not limited to, a muffler, in violation of Section 27150.1 or 27150.2 or the regulations adopted pursuant thereto, shall thereafter be required to install an exhaust system, or part thereof, including, but not limited to, a muffler, which is in compliance with such regulations upon demand of the purchaser or registered owner of the vehicle concerned, or to reimburse the purchaser or registered owner for the expense of replacement and installation of an exhaust system, or part thereof, including, but not limited to, a muffler, which is in compliance, at the election of such purchaser or registered owner. 27150.6. The department shall make every effort to obtain federal assistance to carry out the provisions of Sections 27150.1, 27150.2, 27150.3, 27150.4, and 27150.5. 27150.7. A court may dismiss any action in which a person is prosecuted for operating a vehicle in violation of Sections 23130 or 23130.5 if it is found that the vehicle was equipped with an exhaust system certified pursuant to Section 27150.2 and that the defendant had reasonable grounds to believe that the exhaust system was in good working order and had reasonable grounds to believe that the vehicle was not operated in violation of Sections 23130 or 23130.5. 27150.8. The manufacturers of motorcycles and motorcycle accessories shall, prior to the sale or offering for sale of any motorcycle exhaust system or part thereof, including, but not limited to, a muffler, certify to the department that the exhaust system or part thereof is in compliance with the standards and regulations adopted by the commissioner which are applicable to such exhaust systems or parts thereof and which are in effect at the time of the first offering for sale at retail. The content and form of the certification shall be in accordance with procedures adopted by the commissioner. 27151. No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor of such vehicle so that the vehicle is not in compliance with the provisions of Section 27150 or exceeds the noise limits established for the type of vehicle in Article 2.5 (commencing with Section 27200) of this chapter. No person shall operate a motor vehicle with an exhaust system so modified.