Section 6820 - Operation of OHVs - Without spark arrestor type muffler(a) A person shall not operate an OHV unless such OHV is equipped with a spark arrestor type muffler, in good working order and in constant operation, from which noise emission under 60% of the maximum RPM, measured at 50 feet at right angles from the vehicle path on a constant speed pass, by measurement does not exceed 88 DBA on a sound level meter which meets the requirements of ANSI-514197, using procedure and ancillary equipment therein described. During the test procedure, the ambient sound including wind effects due to sources other than the OHV being measured shall be at least 10 DBA lower than the anticipated level of the test OHV. A vehicle subject to this chapter, manufactured or assembled after January 1, 1978, and used, sold or offered for sale in this State shall conform to the noise emission levels of this chapter unless preempted by federal E.P.A. legislation.(b) Competition vehicles shall be exempted from this section only while in competition.61 Del. Laws, c. 142, § 6.;