Vehicle rollover accounts for a significant percentage of fatal accidents in the USA and worldwide. In this paper, two rollover indexes are proposed and analyzed. The first rollover index estimates the actual Lateral Transfer Ratio (LTR) while the second, referred to as 'Predictive Lateral Transfer Ratio' (PLTR), incorporates the predictive influence of the driver's steering input, thus allowing the actuator to respond faster to the rollover scenario. Both algorithms are compared in open loop and closed loop simulation environment using a baseline control system. The PLTR is shown to be superior in preventing rollover under a number of different cornering maneuvers. The vehicle used for simulation is a large SUV with a top-loaded condition. Preliminary experimental results comparing the two algorithms are also presented.