Explanation: In a regulation stockcar race, 7 members of a pit crew are allowed "over the wall" – that is, onto the pit lane to service a car – during a race. Pit stops can entail refueling, tire changes, repairs, mechanical adjustments and a driver change. Pit stops allow cars to carry less fuel, which makes them lighter and faster. During a stockcar race, cars can travel at 150 feet per second, which means that a ten-second pit stop will cause a car to lose approximately one quarter of a mile to its competitors. This is why pit crew teams must carefully consider the costs of making a pit stop when planning their pit strategy. And, because even the slightest of changes can make a world of difference in a car's performance, mechanics must be extremely sharp-minded and detail oriented.