Work Zone Capacity Estimation for High Truck Volume Routes in Arkansas: Predicting Highway Capacity through Work Zones With High Truck Volumes and Reduced Lane Geometry Based Upon Local Conditions

Work zones on freeways are estimated to contribute to nearly 24 percent of non‐recurring delay.  Prior to 2010, the Highway Capacity Manual (HCM) provided limited guidance on vehicular capacity impacts for freeway work zones.  Simplified methodologies estimated capacities for short and long term freeway work zones.  Previous research (MBTC 2025) conducted by ARDOT during the 1999 Interstate Rehabilitation Program (IRP) found that there are many other factors influencing delay in freeway work zones.  The need to consider factors such as truck percent, work times by time‐of‐day and day‐of‐week, presence of law enforcement, Intelligent Transportation Systems (ITS), work zone configuration and duration, and the intensity of construction activities, in estimating work zone capacities has long been recognized in the industry.  Until 2016, existing analysis methodologies that estimate capacity through work zones did not specifically consider the impacts of high volumes of heavy vehicles.  The recently published HCM 6th Edition, 2016, provides a more detailed methodology to estimate work zone lane capacities but has not been corroborated for Arkansas freeways, where high volumes of heavy vehicles are present.  Title 23 CFR Subpart J – Work Zone Safety and Mobility requires that States develop procedures to address work zone delays. The primary intent of this research was to establish a correlation between work zone lane capacity and the presence of high volumes of heavy trucks on Arkansas freeways.  The secondary intent was to examine work zone traffic data collection methods, both existing at the time of research initiation, and evolving, to determine the feasibility of economically obtaining and utilizing work zone traffic volume and speed data.  Lastly, applications for the use of this data in day to day traffic analysis functions by the Transportation Planning and Policy Division of ARDOT were investigated.