This was the final season for the non-common template bodies. The following season would require all manufacturers to use the same roofline. The most significant rule change for 2002 was the implementation of the one-engine rule for race weekends. At a race event, cars would now be required to practice, qualify, and race with the same engine. The rule banned separate "qualifying engines" (and "practice engines"). Unapproved engine changes during the weekend would be met with a grid penalty. Before the start of the race, cars that changed engines would be forced to move to the rear of the field before the green flag. The rule was an effort to reduce costs, and potentially save crews valuable time during the course of a race weekend.