A web-based study assessed pilots' ability to learn and remember traffic symbols that may be shown on a Cockpit Display of Traffic Information (CDTI). These displays convey data obtained from Automatic Dependent Surveillance-Broadcast (ADS B) and related Aircraft Surveillance Applications System (ASAS) technologies, as well as other surveillance data sources. Three aspects of using the traffic symbols were evaluated: intuitiveness, ease of learning, and ease of remembering the symbols. Four symbol sets were tested, each with approximately 22 symbols. Each participant saw only one of the four symbol sets. The sets used different visual features of the traffic symbol to represent the Directionality, Data Quality, Air/Ground State, Alert Level, Selection State, and Pairing State of nearby aircraft.