This provision is both an "objective emission" control and a "subjective immission" control with a curfew. It can apply to both public and private properties. Since these vehicles can move in large open areas, an "objective" control, limiting maximum sound levels at a fixed distance is appropriate. Since they also can move in bounded areas near residences, a "subjective" control is appropriate. Numerous states and communities have "objective" controls; the most common maximum level is 78 dB(A). Federal law (36 CFR 2.18) regulates snowmobiles on federal property at 78 dB(A), so states and communities are free to regulate snowmobile sound levels on their property. Lincoln NE (Section 8.24.110) limits levels to 78 dB(A). Maine (Section 13112, Chapter 937) exempts snowmobiles at sanctioned racing events. Illinois (625 ILCS 40 Sec. 4-4)does also.