An elevator system 40 includes an over-acceleration and over-speed protection system capable of triggering a machine room brake and a safety trigger when over-speed or over-acceleration conditions are detected. The system includes a speed detector 42 and an acceleration detector 44. Based upon sensed speed and sensed acceleration, the controller 48 calculates a filtered speed of an elevator mass such as an elevator car 16 or counterweight, and compares the filtered speed to the threshold speed to determine whether an over-speed condition has been reached. The controller 48 activates a machine room brake when an over-speed condition exists, and engages an elevator safety 70A, 70B when it determines that the elevator mass is still in an over-speed condition after the machine room brake has been activated.