(Series: 10 Dangerous Practices to Avoid While Driving)
More people than you may think drive for a few seconds at a time with their knees. Usually, they need both hands for something else for a short period of time. In one account we read online, a person said they had seen someone actually driving down the freeway reading a newspaper which would require both knees to steer.
While driving with your knees might be convenient, it is very dangerous. It simply is not possible to react to changes in traffic or even execute proper driving with your knees.
Choose to drive safely. Use your hands instead of your knees.