Active suspension technologies are well known for improving ride comfort and handling of ground vehicles relative to passive suspensions. They are ideally suited for mitigating single-event road obstacles. The work presented in this thesis aims to develop a structured approach for finding the peak force and bandwidth requirements of actuators for active suspensions, to mitigate single-event road obstacles. The approach is kept general to allow for application to different vehicle models, ride conditions and performance objectives. The current state-of-art in active suspensions was first evaluated. Based on these findings, the objectives of the simulation models and approach was defined. A quarter-car model was developed in Matlab to simulate the behavior of active suspensions over unilateral boundary conditions due to different road obstacle profiles. The obstacle profiles were obtained from existing standards and literature and then processed to replicate the interaction of tires on road. A least-mean-squares (LMS) algorithm for adaptive filtering, with the help of look-ahead preview was used to determine the ideal control force profile to achieve the performance objective of the active suspension. A case study was conducted to determine the requirements of the actuator in terms of bandwidth and peak force for different single-event road obstacle profiles, vehicle speeds and look-ahead preview distances. The results of the study show that the vehicle velocity and type of road obstacle have a strong influence on the required peak force and bandwidth of the actuator, while look-ahead preview will be much more important for real time controller implementation.