Memory retention of drivers was tested for traffic- and traveler-related messages displayed on an in-vehicle information system (IVIS). Three research questions were asked: (a) How does in-vehicle visual message format affect comprehension? (b) How does message format affect memory retention? and (c) What impact does driver age have on recall of in-vehicle visual messages? Nine younger (less than 30 years old) and nine older (65 years old or older) drivers participated in the experiment. As subjects steered the Battelle Automobile Simulator, an IVIS presented traveler-related messages. Two types of messages, symbols and text, were presented. Message recognition was tested immediately or 50 sec after the message left the IVIS. Except for low comprehension symbols, driver recognition scores on both text and symbol messages were similar. Younger drivers scored higher than older drivers in identifying the meaning of messages, particularly in the 50-sec question delay condition. Latency to respond to the questions and confidence in the responses were also affected by question delay, with longer response latencies and lower self-rated confidence scores for the longer delay conditions. Message presentation did not degrade vehicle control.