Since it is harder to move heavier objects than lighter objects, the weight of the driver is factored into the total weight of the car and therefore influences the speed of the car. However, this influence may be essentially negligible.
According to an article on NASCAR's website, a lighter weight advantage may be negligible on certain courses, including the Daytona course. Driver weight has become a topic of conversation since Danica Patrick's success in the car racing circuit. For drivers under 180 pounds, weight must be added to the car to make the weight of the car plus driver equal 3,330 pounds. However, weight tends to matter most during acceleration, not when the car is at full speed.