Is there any strategy or reason to draft another car in NASCAR races?
It saves fuel since the car in front has to spend more energy to cut through the air resistance while the car drafting does not (as much).
The low-pressure wake behind a group's leading car reduces the aerodynamic resistance on the front of the trailing car allowing the second car to pull closer. As the second car nears the first it pushes high-pressure air forward so less fast-moving air hits the lead car's spoiler. The result is less drag for both cars, allowing faster speeds.