Upgrading the FHWA Work Zone Model Version 2.0 and Validating its Performance Along I-91 in Springfield, Massachusetts

Freeway work zones can have significant safety and operational impacts. To mitigate these, planners and engineers rely on accurate simulation tools to assess various work zone design and scheduling alternatives. Microsimulation models are often used to predict traffic conditions along freeways, however, they were not created to replicate car-following through work zones and therefore cannot be used to accurately predict work zone impacts. So that pracitioners can use microsimulation to better predict work zone impacts, FHWA created the Work Zone Driver Model v1.0 (FHWA v1.0) – a software that overrides car-following in commercial microsimulation software packages for work zone segments. FHWA v1.0 was tested in a 2017 case study. Results showed acceptable performance, however, there were opportunities to improve the software’s usability and accuracy. Findings were used to upgrade the software and create the FHWA Work Zone Driver Model v2.0 (FHWA v2.0). This paper demonstrates the enhanced capabilities of FHWA v2.0 by interfacing with VISSIM and recreating the 2017 case study, testing its performance along the same interstate work zone in Springfield, MA. FHWA v2.0’s performance was compared to field data, to wiedemann 99 (W99), and to FHWA v1.0. Performance metrics were selected to align with state DOT work zone management efforts. Results show improved performance from FHWA v2.0 as it predicted queue lengths, queue locations, and travel speeds more accurately than FHWA 1.0 and W99. The enhanced software also addressed some of the variability and merging issues described in the 2017 case study. Next steps are described.