(1) A vehicle exceeds Visible Emission Standard I if the vehicle produces any visible emissions that include any gases or particulates, other than uncombined water, which separately or in combination are visible upon release to the outdoor atmosphere.
(2) A vehicle exceeds Visible Emission Standard II if the vehicle is operated at an elevation described under this subsection and the vehicle produces a visible emission in excess of that allowed under this subsection. Visible emissions limited under this subsection include any gases or particulates, other than uncombined water, which separately or in combination are visible upon release to the outdoor atmosphere. The limitations on visible emission under this subsection are limits on the percent of transmitted light that is obscured by the visible emission. A vehicle violates the standards under this subsection if the vehicle does any of the following:
(a) While operated at an elevation of 3,000 feet or less, releases emissions that obscure more than 10 percent of transmitted light. A vehicle is not in violation of this paragraph if the vehicle releases emissions that obscure 40 percent or less of transmitted light for not longer than seven consecutive seconds.
(b) While operated at an elevation of over 3,000 feet, releases emissions that obscure more than 20 percent of transmitted light. A vehicle is not in violation of this paragraph if the vehicle releases emissions that obscure 60 percent or less of transmitted light for not longer than seven consecutive seconds. [1983 c.338 §486; 1985 c.16 §253]