A study of traffic sign symbols was completed recently at the FHWA Turner-Fairbank Highway Research Center in McLean, Virginia. As part of this research, four work zone traffic control warning signs (Pavement Width Transition, Flagger Ahead, Low Shoulder, and Uneven Pavement) were selected for redesign. Several alternatives for each sign were tested in a laboratory experiment. Legibility distance, comprehension, and preference data were collected for each alternative. The results of the study indicate that the current symbolic designs for Pavement Width Transition and Flagger Ahead are superior to the alternatives tested and should be retained. The current symbolic sign for low shoulders was found to be inadequate (22 percent comprehension), but an acceptable alternative was not found. Given the infrequent use of this sign and the difficulty of communicating this concept to the driver, the use of the alphabetic Low Shoulder sign is recommended. For the Uneven Pavement sign, an improved symbolic design was identified and is recommended.