The Human Factors Group studies the interactions of the driver, the vehicle, and the environment. The underlying rationale is that well-designed vehicles and roadways make the driving task safer, easier, and more efficient. To achieve this end, automotive human factors experts need to understand driver capabilities and limitations. The UMTRI Human Factors Group develops models of driver capabilities related to vision, perception, decision making, and psychomotor performance incorporating the effects of factors such as age, sex, fatigue, and alcohol. The group then uses knowledge of these capabilities to develop guidelines for well-designed vehicle components and driving environments.