Preliminary drag coefficient results for variable message signs with various depth ratios, aspect ratios and wind approach directions are presented. These results based on large-scale testing, show a consistent decreasing trend in the drag coefficient with increasing depth ratio. This confirms the hypothesis that partial reattachment of flow over a prismatic variable message sign reduces the drag force resulting in a smaller drag coefficient for use in design. Results for flat panel models (depth ratio = 0.1) are qualitatively in agreement with previous research studies.
