Executive summary For nearly 50 years after the introduction of the automobile@ drivers struggled with the steering wheel during low-speed parking maneuvers. As automobile performance rapidly improved from the introduction of cars over a hundred years ago@ drivers were also seeking improvements in handling stability at high speeds. The introduction of larger@ more powerful engines along with larger and heavier vehicles led engineers to seek a way to help overcome the rack loads that were making it more difficult to turn the steering wheel. In the 1950s@ General Motors introduced the hydraulically assisted power steering system. This system used a recirculating ball steering system coupled with a belt-driven hydraulic pump. The hydraulic pressure created by the rotary vane pump reduced the steering effort by the driver required to overcome the rack load on the steering system. An important design aspect of the power steering system was that it provided steering stability at high vehicle speeds because the driver had hydraulic pressure assisting in the control of the linkage. A second system@ a rack and pinion steering system@ was eventually developed and used in many lighter and sportier vehicles. For many years@ this system did not require any power assist but eventually@ it too began to use a hydraulic assist. Today@ a revolution is taking place in steering technology in the automotive industry. For the past 50 years@ steering technology has focused on using hydraulics to assist the driver in steering the vehicle. Automotive engineers have done a superb job of creating steering systems for all weight and size classes of vehicles ranging from sub-compact through large sport utility vehicles and large trucks. However@ during the past decade the focus has been changing to using electric motors to supply the assist to steering systems. This has been especially true in Europe and Asia@ where many of the cars are lighter and smaller than in the United States and fuel economy is a very important consideration. In addition@ packaging is an important consideration in the use of electric steering. A number of electric power assisted systems are under development. The two that are seeing the most widespread use are the electrohydraulic power assisted system and the column-mounted electric power assisted system. A number of other systems are under development for various sized vehicles. Many suppliers are starting to receive orders for electric power assisted steering systems as new models and platforms are developed. The addition of electric power assisted steering can reduce fuel consumption by 5 to 15%@ depending on the vehicle. Currently@ the vehicles adopting the use of the column-mounted power assist steering are the lighter (less than 1000 kg [2205 lb]) vehicles in the sub- to compact-size range. Electrohydraulic power assisted steering can be used in various vehicles because it requires only the replacement of the belt-driven hydraulic pump with an electric motor and control electronics. Electric steering is expected to be used on almost 50% of new vehicles in Western Europe by 2005. North America is beginning to use electric steering in some vehicles@ but it is expected that it will take another decade before a substantial percentage of vehicles will be equipped with electric steering. The introduction of electric steering is a step in the evolution of the automobile toward steer-by-wire. As the 42 V electric system also is introduced into the mass production market in a few years@ it may accelerate the use of electric power assisted steering in larger@ luxury vehicles.