A chassis dynamometer is a device used to measure the power output and performance of a vehicle's engine while it is in motion. It consists of rollers that simulate road conditions, allowing the vehicle to drive over them. As the wheels turn, sensors capture data on speed, torque, and horsepower, providing valuable insights into the vehicle's performance. These dynamometers are commonly used in automotive testing, tuning, and research. They help engineers and mechanics assess how modifications affect a vehicle's performance and ensure that it meets regulatory standards. By analyzing the data, they can optimize engine performance and improve fuel efficiency.