This paper provides a critical review of tire test techniques, test equipment, data processing methods, and mathematical models for obtaining data and describing tire cornering properties. It examines applicability of this data for evaluation of vehicle directional response properties and shows how test and data processing methods influence tire parameters used in simulations with models. Mathematical relationships between tire parameters and vehicle directional response parameters such as steering sensitivity are shown. Fundamental differences between conditions prevailing in testing, hypothetical assumptions used in mathematical models, and actual tire operating conditions on a vehicle are discussed. The need for transient tire measurements and modeling for transient conditions is also shown.