This SAE Information Report relates to a special class of automotive adaptive equipment which consists of modifications to the power steering system provided as original equipment on personally licensed vehicles. These modifications are generically called “modified effort steering” or “reduced effort power steering.” The purpose of the modification is to alter the amount of driver effort required to steer the vehicle. Retention of reliability, ease of use for physically disabled drivers and maintainability are of primary concern. As an Information Report, the numerical values for performance measurements presented in this report and in the test procedure in the appendices, while based upon the best knowledge available at the time, have not been validated.