Assessing the effects of a rectangular rapid-flashing beacon on vehicle speeds along a four-lane divided highway

In 2008, nearly 31% of vehicle fatalities were related to failure to adhere to safe vehicle speeds (National Highway Traffic Safety Administration (NHTSA), 2009). Two studies were conducted to evaluate the effects of a Rectangular Rapid-Flashing Beacon (RRFB) triggered by excessive speed on vehicle speed using a combined alternating treatments and reversal design. Experiment 1 assessed the RRFB's impact on speeds as compared to baseline conditions only. Experiment 2 compared the RRFB to two standard beacon configurations. Both experiments were conducted at the same site during approximately the same time period and both employed the same data collection methodology. The results of Experiment 1 showed that the RRFB resulted in better speed compliance as compared to baseline conditions. Experiment 2 indicated that the RRFB appeared to result in improved speed compliance over both the standard beacon configurations. Overall results of the two studies indicate that the RRFB may be a viable new intervention for reducing speed in transition zones and entries to roadway curves.