This paper details a unique method for measuring three key vehicle states -wheel slip, body sideslip angle, and tire sideslip angle -using GPS velocity information in conjunction with other sensors. Based on initial noise data obtained from the system components, a prediction of the accuracy of these new measurements is obtained. Subsequent experiments validate both the methodology for obtaining the measurements as well as the error analysis. The experimental results for the GPS velocitybased sideslip angle measurement compare favorably to theoretical predictions, suggesting that this technique has merit for future implementation in vehicle safety systems.