Presumably the fine should cover it. The customer service costs are pretty constant regardless of impound duration, and you locate the impound in a place where

Presumably the fine should cover it. The customer service costs are pretty constant regardless of impound duration, and you locate the impound in a place where a big empty lot with a fence is not expensive. If space needs to be made, the decision of when a car can be removed should be made by someone with no financial stake in the outcome.