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

Abstract

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 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. DOT F 1700.7 (8-69) (TRB, 1975; TRB, 1996). Evidently, the assumption requires the qualification that speed is a function of density, but only at equilibrium. Because equilibrium can rarely be observed in practice, a satisfactory speeddensity relationship is hard to obtain, and it is often assumed or inferred theoretically. Higher-order Continuum ModelsThe higher order models take into account acceleration/deceleration and inertia characteristics of traffic mass by replacing the equilibrium speed-density relationship with a momentum equation (Whitham, 1974; Payne, 1979 where v is the viscosity coefficient. (Whitham, 1974; Payne, 1979 -v,) Cl dk,where U, is the equilibrium speed and T is the relaxation time. Typically, the value of U, is calculated using an empirical speed-density relationship developed from field data.The left-hand side of the above equation gives the acceleration/deceleration rate of the flow observed at location x. The acceleration/deceleration rate is a sum of several components:

Indiana Lane Merge System - Warrants for Use

“…An approximate estimate of density for two lane rural freeways in Indiana (Tarko et al, 1998) is used for the purpose,…”

“…The length of the congested segment can be calculated using the following equation, (Tarko et al, 1998): The maximum overflow queue is estimated using:…”

Synthesis of Unconventional Dynamic Merge Metering Traffic Control for Work Zones

“…The primary intent of the late merge is to reduce the road rage between early and late mergers by informing drivers that it is permissible for traffic to travel in both lanes to the merge point. A comparison study revealed that the conflict rates are substantially lower with the late merge and the capacity of the Late Merge can be nearly 20 percent higher than that of the conventional merge [4]. An evaluation conducted by Beacher et al recommended that late merge should be considered for 3-to-1 lane-closure configuration only after a sound methodology for deployment has been developed and tested in the field [5].…”

“…Several field testing studies and literature reviews [2][3][4] indicate that, of the above strategies the late merge and dynamic late merge methods are better ones for traffic control for work zones. The late merge is designed to encourage drivers to use either the open or closed lane until they reach the merge point at the lane closure taper.…”

Multi-Criteria Evaluation in Support of the Decision-Making Process in Highway Construction Projects

“…The Early Merge traffic control system uses a series of traffic signs placed in advance of the taper area, creating an enforceable no passing zone to encourage motorists to make an early merge, as shown in The results of a simulation study by the University of Purdue indicated that travel times were longer for the Early Merge concept (Tarko et al, 1998 …”