@neededlotus5, thank you for your feedback.
The smoke is applied directly to the exhaust pipes. I use an original feature from the game map. I tried to implement the feature you mentioned, but I can't cut the smoke with the engine off, and I can't change the smoke volume according to the trucks' acceleration or gear changes.
The mod presented is the best I can do.
Sorry.

would be cool if the smoke only worked when the engine is running

@XEBEKzs, making another clearer mod will practically disappear.
I'll keep it this way to maintain the same standard I set for Euro Truck Simulator 2. Have fun!

It's better now. You could add another version of the mod Super Light Smoke to make the smoke even brighter.

This add-on needs to be used in conjunction with the "Smoke in my Trucks" mod by Carlitos and given a higher priority 👍