For how long should a vehicle not send out visible smoke?

A vehicle should not emit visible smoke for at least 10 seconds while in operation. The rationale behind this time frame is tied to vehicle emissions regulations and environmental concerns. If a vehicle emits visible smoke, it typically indicates that there is a problem with the engine, fuel system, or other components that could be causing inefficient combustion or excessive pollution.

Maintaining a standard of 10 seconds without visible smoke is essential in promoting cleaner air and reducing the environmental impact of vehicles on the road. Continuous visible smoke beyond this duration may trigger inspections or penalties, as it suggests that the vehicle may not be in compliance with emissions standards. For good vehicle maintenance and operating conditions, it's crucial that vehicle owners ensure that their vehicles run cleanly to minimize emissions.