Traffic Alert and Collision Avoidance Systems(TCAS) displaysdepict traffic advisories, resolution advisories, and information on other aircraft. Symbols for other aircraftinclude the proximate status indication where the symbolsof"proximate" (close) aircraftare filled and the symbols of "non-proximate" (more distant) aircraftare not filled. This web-based study examined the value of the proximate status indication as represented by symbol fillto assess implications for Cockpit Displays of Traffic Information (CDTIs), and found no advantage for it, only a disadvantage