Analysis of Speed Profiles and Evaluation of Dynamic Signs in Kansas Work Zones

Work zones are essential for maintaining and improving roadways in the United States. Although reduced speed limits are used throughout work zones to increase worker and driver safety, motorists often do not obey these speed limits. From 2016 to 2017, 799 work zone fatalities occurred, an increase of 3%, with vehicle speed as a main contributing factor. These fatalities cost construction industries up to $3.5 billion a year. These expenses result from on-the-job crashes and cover property damage, medical/legal expenses, and loss of productivity (Douglas, 2018). The purpose of this study was to evaluate the effectiveness of dynamic speed signs that attempt to reduce vehicle speeds through work zones. A computer program was developed to trace vehicles through a work zone to determine the effectiveness of following vehicles through a work zone versus evaluating overall vehicle data when evaluating the dynamic speed signs. This study utilized three work zones: Work Zone 1 (computer program) and Work Zones 2 and 3 (dynamic speed signs). Results showed that overall data evaluation more effectively determined vehicle speed than vehicle evaluation via the computer program. While Work Zones 2 and 3 both showed reductions in vehicle speed after the dynamic speed signs were placed, reduced speeds in Work Zone 3 were closer to the posted speed limit than Work Zone 2. In addition, results showed that passenger cars were most likely to exceed work zone speed limits, followed by speeding tractor-trailer trucks.