Shauna Hallmarkshallmar@iastate.edu email >
Omar Smadismadi@iastate.edu email >
About the research
This multi-phase study utilized Second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) data to evaluate the impact of traffic control devices in reducing driver speed in work zones. The main advantage to the SHPR2 NDS data is that on-road driver behavior was captured and can be used to evaluate how drivers behave in various situations. The study included four different analyses. The first evaluated where drivers began reacting to various work zone traffic control devices. The second assessed how drivers changed speed upstream to immediately downstream as they encountered various traffic control devices. The third assessed how drivers react when they encounter the back of a queue and the fourth developed speed based on work zone characteristics such as presence of barriers.
The project also includes a toolbox that summarizes information about work zone traffic control devices, countermeasures, and work zone features that have a demonstrated impact on speed in work zones. Features were identified through a survey of the literature. Additional information for some of the features and countermeasures was gained through the various analyses of SHRP2 data conducted through this project. Guidance from the work zone traffic control manuals for various states was summarized when appropriate. Recommendations for use of each feature or countermeasure relevant to addressing speed in work zones was developed by the team and reviewed by work zone experts and the project panel.