The relationship of the steering controllability characteristics of domestically-produced subcompact, compact, and intermediate size automobiles to specifications on yaw-rate gain and response time as developed in NHTSA research programs is examined through (1) an analytical survey of the yaw response of 1977 vehicles and (2) open- and closed-loop testing of 3 selected vehicles in modified and unmodified conditions. It is found that, with the exception of some vehicle models equipped with manual steering, the directional performance characteristics of currently produced subcompact, compact, and intermediate size cars lie within the 'optimum' region that has been defined through NHTSA research. It is recommended that further effort in defining safety-related handling requirements is needed before implementing vehicle performance specifications.
Abstract