Turning the wheels in early cars took real effort, and the larger and heavier the vehicle, the harder it was to steer. In 1926, Francis Wright David developed a power steering system, which linked the steering wheel to a hydraulic system to move the wheels. The system did make it easier for drivers to steer, but automakers did not adopt it because of its cost. However, the needs of the military during World War II spurred automakers to begin including power steering systems, and the first commercially available power steering system debuted in 1951 in the Chrysler Imperial. Other automakers decided to adopt the system as well, and today every car comes with power steering.