It would be GREAT if you create a mini trash bin for the car that can be easily installed. There are a few products out there, but they don’t work well. Some are too small and low quality and not worth the investment.
You could make a mini trash can with disposable bags that hold well and don’t fall off when you put in trash. Big enough to hold the typical trash you would have in a car, but not too big for convenience. As you can see on the picture, you could make them with a glue on back for easy installation wherever is more convenient for every individual.