In response to concerns over the number of runway incursions and runway conflicts at U.S. airports, the FAA is sponsoring research and development of safety systems for the airport surface. Two types of safety systems are being actively pursued, a tower cab alerting system and a runway status light system. The tower cab alerting system, called the Airport Movement Area Safety System (AMASS) is currently undergoing initial operational evaluation at several major airports. It provides aural and visual alerts to the tower cab to warn the controllers of potential traffic conflicts. The runway status light system is currently in the development phase, with initial operational suitability demonstrations planned at Dallas/Fort Worth International Airport during FY2003. Intended to offer protection in time-critical conflict scenarios where there is not enough time to warn the aircrews indirectly via the tower cab, the runway status light system provides visual indication of runway status directly to the cockpit; runway entrance lights warn pilots not to enter a runway on which there is approaching high-speed traffic; takeoff-hold lights warn pilots not to start takeoff if a conflict could occur. Both systems operate automatically, requiring no controller inputs. Activation commands for alerts and lights are generated by the systems' safety logic, which in turn receives airport traffic inputs from a surface surveillance and target tracking system. Accurate traffic representation is essential to meet system requirements, which include high conflict detection rate, prompt and accurate alerting and light activation, low nuisance and false alarm rates, and negligible interference with normal operations. This report analyzes the effect of the two fundamental surveillance performance parameters-position accuracy and surveillance update rate - on the performance of three different surface safety systems. The first two are the above-mentioned tower cab alerting and runway status light systems. The third system is a hypothetical cockpit alerting system that delivers alerts directly to the cockpit rather than to the tower cab. The surveillance accuracy and update rate requirements of these three systems are analyzed for three of the most common runway conflict scenarios, using realistic parameter values for aircraft motion. The scenarios are 1) a runway incursion by a taxiing aircraft in front of a departure or arrival, 2) a departure on an occupied runway, and 3) an arrival on an occupied runway. Runway status lights are especially effective at preventing incursions and accidents between takeoff or arrival aircraft and intersection taxi aircraft. Tower cab alerts are effective at alerting controllers to aircraft crossing or on a runway during an arrival. Runway status information provided directly to the cockpit will be required for the case where a previous arrival or a taxi aircraft fails to exit the runway as anticipated shortly before the arrival crossed the threshold. (not complete)