Though opinions on impound racing can be mixed, NASCAR officials put a lot of thought into its implementation. Rule changes are never quick and easy -- it takes time to explain and enforce the new rules, so NASCAR didn't formulate the impound rule without reason.
According to NASCAR, implementing impound races was a way to keep racing teams focused on the best setup for the race and to enhance competition. The idea was, and still is, to make racing a level-grounded sport, ensuring that teams with little money can compete with well-funded teams. Impound racing was seen as a way to curb expenses and save money. By impounding the car, a team is relieved of the need to have a qualifying setup and a race day setup.
It isn't unusual for a high-dollar team to have two complete setups. One setup is used to qualify, and then the team tears down that setup and rebuilds it for the race [source: Shinzawa]. Not only is this practice expensive, but some feel it takes away from the sport. When doing this, teams can build setups meant to make their car better at qualifying, but not necessarily ensure they will perform well at the race [source: Siska]. But with the impounding rule in force, the car is already built for the race when it goes through the qualification trials.
Now, let's look at the different types of restrictions that are placed on teams during impound races.