To examine the issues with collision avoidance during closely spaced parallel approaches, two related studies have been performed. First, the most hazardous relative positions of aircraft on parallel approaches were identified through fast-time simulations of collision trajectories. Second, a part-task flight simulator evaluation of traffic displays, the need for automatic alerts and for autopilot control of the approach was conducted. While a need was identified for alerting systems to command effective avoidance maneuvers, pilots were found to frequently not conform to the commanded avoidance maneuver, with a resulting decrease in performance. Based on these results, concerns meriting further study are discussed.