What is the maximum allowable exhaust smoke duration for diesel vehicles during acceleration?

The maximum allowable exhaust smoke duration for diesel vehicles during acceleration is set at visible smoke for no more than 5 seconds. This standard is designed to mitigate environmental pollution and ensure that diesel vehicles operate within acceptable emissions limits. Diesel engines are known for producing visible exhaust smoke, particularly during bursts of power or rapid acceleration. Regulating the duration of this visible smoke helps to ensure that vehicles maintain a level of emissions that aligns with both state and federal environmental guidelines.

Allowing visible smoke for a limited duration recognizes the technical limitations of diesel engines while still promoting cleaner air standards. This provision provides a balance between operational performance and compliance with emissions regulations, thereby ensuring that diesel vehicles remain effective for their intended use without contributing excessively to air pollution.