Modeling and Optimization of the Indiana Lane Merge Control System on Approaches to Freeway Work Zones, Part I

Severe traffic turbulence on entry sections of freeway work zones increases the delays and risk of crash. A new Indiana Department of Transportation system called Indiana Merge Lane System (IMLS) creates a dynamic no passing zone on the approach to the freeway work zone through the sequence of DO NOT PASS signs. The system is thought to encourage drivers to switch lanes well upstream of the discontinuous lane taper where the merging maneuver is safer and less intrusive. The IMLS is expected to impact drivers’ behavior, their perception of the traffic conditions, and traffic safety. This research is focused on: (1) drivers’ compliance with the system, (2) delays and travel times on approaches to work zones, (3) optimal configuration of the system, and (4) warrants for the system’s use. The simulation and field studies indicate a significant reduction in the number of merging maneuvers near work zones after the IMLS is applied. Also, the travel time on continuous lanes is reduced. The increased fairness of the system improves the perception of the traffic conditions among the majority of drivers. A slight reduction in the capacity of the merge point is the second finding of the field observations. This finding should be confirmed through long-term measurements of capacity during regular use of the IMLS units. The final report is divided into two parts. Part I presents the performed research, including the simulation model development and simulation experiments. Part II is published as a separate report and contains the system description, guidelines for its use, and rules for its setting. The system description includes presentation of the concept and the system components. The guidelines for the system use provide the traffic conditions where the system is expected to provide benefit. Finally, the manual gives a set of simple rules useful in setting all the system parameters to achieve the maximum reduction in the travel time in the continuous lane.