Driver Response to a Dynamic Speed Feedback Sign on Freeway Exit Ramps Based on Sign Location, Interchange Type, and Time of Day

A series of field evaluations was performed at three freeway interchange ramps in Michigan that possessed significant horizontal curvature to assess the impacts a dynamic speed feedback sign (DSFS) on driver selection and brake response while approaching entering ramp curve. DSFS with 15 in. full-matrix display temporarily installed each exit locations. The programmed same message location, which included number for all vehicles, alternated “Slow Down” vehicles above 40 mph. effectiveness tested across various locations (at point versus 350 ft upstream), types (system service), time day (peak off-peak), light conditions (daylight darkness), vehicle (passenger trucks). Compared pre-DSFS site condition, reduced curve entry speeds improved two In general, greatest beneficial effects behavior were achieved when positioned curvature, during by approximately 2 These findings consistent between system interchanges service interchanges, types. also found be most effective daytime off-peak periods compared peak night. Further evaluation additional locations, considering an expanded set conditions, is recommended.