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Operational and Safety-based Analyses of Varied Toll Lane Configurations

Toll plaza operation is a critical component of roadway operations throughout the United States, as tolls provide both revenue for expansion and opportunity for demand management. Originally cash or physical currency based, tolling has morphed to meet the twentieth century demand in terms of throughput and efficiency in the form of electronic toll collection. Electronic tolling has introduced a new form of driver decision making at toll plazas due to the additional payment choice. Despite the user convenience these facilities provide to consumers, this form of collection has not come without safety and operational concerns. Confusion at the toll plaza, unsafe merging maneuvers, and the unexpected behavior has actually increased certain crash patterns at toll plazas in some electronic tolling facilities. Building upon existing research, further work was completed to quantify the related impacts of electronic toll collection on traffic operations through a microsimulation model, and static evaluation study. While in Massachusetts overall toll plaza crashes are a minimal portion of 200,000 crashes each year in the Commonwealth at less than 0.1 percent of all crashes some toll plazas have higher crash rates than the state wide urban interstate average. Interchange 14 in Weston, Massachusetts had the highest crash rate among state toll plazas. Rear-end and same direction sideswipe collisions accounted for the highest crash numbers between the years 2010 and 2012. Microsimulation of various lane configurations derived from static evaluation feedback on driver decision making created six alternate configurations. Current plaza configuration was verified by the validated VISSIM microsimulation model to be the highest performing in terms of efficiency. A lane configuration with grouped payment lanes provided the best overall performance for alternatives with less than 1 percent difference from the current West Springfield interchange configuration. Static evaluation and microsimulation results pointed to increased efficiency and safety benefits with combination lanes. Additionally, drivers tended to avoid following heavy vehicles through plaza lanes. Motorists were willing to make up to 3 lane changes to avoid queues and may avoid combination lanes as an electronic toll customer if they anticipate a greater delay than an adjacent dedicated electronic lane. Recommendations for future research include: 1) further microsimulation modeling to examine traffic flow and safety impacts at toll plazas under varying traffic conditions and demand with open road tolling lanes strategies; and 2) developing enhancements to VISSIM to address parameter limitations associated with discrete choice modeling at toll plazas.