Evaluation of the Effectiveness of Dynamic Speed Feed Back Signs in Work Zones on High-Speed Kansas Roadways

Work zones are essential to keeping our roadways preserved or reconstructed so that they are safe and efficient. Work zones tend to increase safety risks due to the normal driving’s changing conditions whether short or long-term. In 2017, there were 799 fatalities in work zones; this showed a 3% increase from 2016 (FHWA, 2019). In order to reduce safety risks, reduced speed limits are used throughout work zones. However, different vehicle speeds across a work zone site can increase traffic congestion, delay, increase crashes if not properly signed using temporary traffic control and / or a reduction in vehicle speed. The objective of this study was to evaluate vehicle speed profiles in work zones and determine a dynamic speed feedback sign’s overall effectiveness. Three work zone sites in Kansas were evaluated in this study using multiple pneumatic road tubes. Work zone 1 compared the accuracy of tracing vehicles using a computer program versus manual tracing. Work zones 2 and 3 included a dynamic speed feedback sign to notify drivers they were traveling above the posted work zone speed. Manual tracing of individual vehicles gave researchers more accurate results when evaluating speed. A statistical analysis found that work zones 2 and 3, there were significant speed reductions. However, work zone 3 showed the most consistent reductions and put vehicle speeds closer to the posted speed limit. Additionally, passenger vehicles and tractor-trailer trucks proved to be most likely to exceed the posted speed limit. Overall, the dynamic speed feedback sign was found to be effective in the two work zones analyzed.