Georgia Code Title 40. Motor Vehicles and Traffic § 40-8-181

(a) It shall be unlawful for any person to operate on a public roadway of this state a diesel powered vehicle which discharges into the atmosphere visible emissions resulting in a decrease of light transmission beyond 30 percent, whether emitted from the crankcase, the exhaust system, or from any part of the power system; provided, however, that the light obscuring limitations prescribed in this subsection may be exceeded during periods of acceleration and deceleration not to exceed ten continuous seconds or 1,000 feet.

(b) It shall be unlawful for any person to operate on a public roadway of this state a gasoline powered vehicle which discharges into the atmosphere visible emissions resulting in a decrease of light transmission, whether emitted from the crankcase, the exhaust system, or from any part of the power system; provided, however, that the light obscuring limitation prescribed in this subsection may be exceeded for periods not to exceed ten continuous seconds or 1,000 feet.

(c) Subsections (a) and (b) of this Code section shall not apply to the normal discharge of condensed water vapor.