Impending rollover events are detected based on vehicle roll rate, roll angle and lateral acceleration, and an assessment of the relative polarities of vehicle roll rate and lateral acceleration. When the vehicle roll rate and lateral acceleration are opposite in polarity, the roll rate vs. roll angle thresholds used to distinguish between rollover events and non-rollover events are more sensitive than for conditions for which the vehicle roll rate and lateral acceleration are of the same polarity. Additionally, the roll rate vs. roll angle thresholds are adaptively modified based on roll angle and lateral acceleration to provide increased detection sensitivity under conditions that typically precede a rollover event, and reduced detection sensitivity under conditions for which a rollover event is unlikely.