<P> Originally , many ambulances used a safety orange cross on a square background of reflectorized white to designate them as emergency medical units . This logo was used before national standards for Emergency Medical Personnel or ambulances were established . Designed by Leo R. Schwartz , Chief of the EMS Branch , National Highway Traffic Safety Administration ( NHTSA ) , the Star of Life was created after the American Red Cross complained in 1973 that the orange cross too closely resembled their logo , the red cross on a white background ; such usage was restricted by the Geneva Conventions . </P>
what symbol displayed on ambulances was replaced with the star of life in the 1970 's
a safety orange cross on a square background of reflectorized white