The term "Boston Boot" is an informal term used to describe a car immobilization device. It is commonly used by law enforcement or private security companies to immobilize vehicles of scofflaws or those who have violated parking laws. There are several other synonyms for this device, including wheel lock, parking boot, Denver boot, and vehicle immobilizer. The use of such devices is common in major cities as a means to enforce parking and driving regulations. The goal is to discourage drivers from ignoring the rules of the road and to reduce the number of unpaid parking fines.