The smoke opacity inspection standards for diesel-powered commercial motor vehicles, as established by the Department of Environmental Protection, are as follows:

1. (1) For model years 1991 and newer, the level of peak smoke opacity shall not exceed forty (40) percent; and
2. (2) For model years 1990 and older, the level of peak smoke opacity shall not exceed fifty-five (55) percent.

(Effective September 28, 1998; Amended December 29, 2006)