In addition to my other response: Assuming you just don't know what the difference is between forfeiture and impound, a primary justification for impounding a car in a DUI is that the intoxicated person cannot legally operate the vehicle. It's not uncommon to see an officer allow a sober person to drive the vehicle off of the roadway when there is an authorized driver available--the reason for towing is to prevent it from being a safety hazard on the road. Unless there's new case law that I don't know of, Miranda v. City of Cornelius serves as a friendly reminder that vehicles may not be impounded for the sole purpose of punishing the driver or owner.