This paper provides an overview of the Side impact Research program conducted by Vehicle Methods and Components Department of Ford Motor Company over the past three years. A simple spring-mass computer simulation model is developed for predicting crash behavior of the body side structure of a vehicle impacted on its side by another vehicle. The model was used in determining the degree of structural reinforcement required to effectively reduce body side intrusion of a compact size vehicle. Exellent agreement between the predicted and test results was obtained and the effectiveness of structural reinforcements in reducing occupant cushioning requirement was demonstrated.