Investigating the impacts of I-66 Inner Beltway dynamic tolling system

Abstract This paper investigates the impacts of the tolling policy on Interstate 66 and its alternative routes in the immediate impact areas. The I-66 inside the Capital Beltway (I-495) is a major corridor connecting Northern Virginia to downtown Washington, D.C. Starting December of 2018, all lanes on this stretch of I-66 transitioned from High-Occupancy-Vehicle (HOV) into High Occupancy/Toll (HOT) in the direction of peak traffic during rush hours. Toll amounts are set dynamically according to congestion levels, and high occupancy vehicles (two people and more) are exempt from the toll. This study first introduces the study area and uses multiple data sources, including historical toll and probe speed, to describe the current traffic conditions on I-66 Inner Beltway and its alternative routes. Additionally, a comprehensive before-after study is provided to evaluate how conversion from HOV into HOT has effectively combated congestion and improved travel time reliability in the study area.