during a pit stop, slowing them down. NASCAR pit crew roles The crew chief is the leader of the pit crew. They are responsible for all aspects of the crew, car set-up (from the construction of the car at the shop down to in-race handling adjustments), and at-track activities. They call the team's pit strategy (usually with the help of one or more race engineers who monitor telemetry) and will hire a pit crew coach to help coordinate the pit stops and train the pit crew members to stay in good physical shape. NASCAR regulations dictate that only five individuals can go "over the wall" to service a racecar during a pit stop. The tool limits on the crew are two impact wrenches, one jack, and two cans of gasoline. Other tools may be used if needed, but major work must be performed in the garage area. An important tool used by the crew chief is referred to as the pit box, but colloquially called the "war wagon". The pit box is generally equipped with flat-screen monitors and the television broadcast of the event. These tools are used to help analyze the car up close during any moment of the race. The car chief performs a majority of the scheduling and day-to-day preparations at the shop prior to the race weekend. This person is responsible for managing the crew throughout the weekend, ensuring that the car meets all of NASCAR's inspection requirements, and overseeing changes to the car requested by the crew chief or the team engineer. This role is similar to that of a chief operating officer's in general. If the crew chief is not able to attend the race, the car chief will occasionally serve as interim crew chief. The jackman raises each side of the car so that the tires can be replaced. This person must do this quickly with the use of a 22-pound (10 kg) floor jack. while also removing and reinstalling the rear tires since the removal of the rear tire carrier. The jackman signals for the driver to leave the pits by lowering the car. The two tire changers remove and tighten the lug nuts on the tires using a specification impact wrench (or "air gun") made by Paoli (prior to the 2018 season, air guns were open to development, and top teams often built their own from scratch). One tire changer is