Fracture of the pelvis often results in major hemorrhage and even death in victims of motor vehicle trauma. In the hospital emergency department, diagnosing a fracture of the pelvis is difficult because the patient may be unconscious or disoriented, have multisystem injury, may not demonstrate bruising or other physical findings, and because the attendant bleeding is often retroperitoneal. This paper develops information from a diagnostic source that is currently almost unused: the vehicle. Accident statistics files from the National Accident Sampling System are used to relate pelvic fractures and dislocations with vehicle information. Collision type, occupant seating position, intrusion, entrapment, restraint use, age, and sex are analyzed as they bear upon the likelihood of pelvic fracture. Linear discriminant analysis is used to form simple equations that predict whether the patient will have a fracture or dislocation of the pelvis.