Design and evaluation of an Arterial-Friendly Local Ramp Metering System

Project Abstract

To address the widespread concern of an on-ramp control’s negative impacts (e.g., ramp queue spillover) on a neighboring arterial’s traffic conditions, the research team, with the support of Maryland Department of Transportation State Highway Administration's (MDOT SHA’s) staff/engineers, has recently developed an innovative Arterial-Friendly Ramp (AF-Ramp) metering system, which aims to maximize the total benefits of the freeway and arterial users with both an optimized ramp metering rate and a coordinated signal plan for intersections within the ramp-impact area. Different from current ramp-metering models in the literature and in practice, the proposed AF-Ramp system includes the target freeway segment, its on-ramp, and neighboring intersections in one integrated control environment, and converts them from competing for available roadway capacity to a coordinated mode that maximizes their total benefits. To ensure the AF-Ramp system’s effectiveness in addressing complex, local-specific traffic patterns, it is essential that a rigorous and extensive field evaluation be conducted with respect to the system’s key model parameters and embedded assumptions. The coordinated relationship between the system’s three primary models, from estimating the freeway’s remaining capacity for ramp flows to the optimization of ramp metering rate and intersection signal plans, can also be assessed with the field data.

Universities Involved

University of Maryland, College Park

Principle Investigators

Dr. Gang-Len Chang

Funding Sources and Amounts

USDOT: $100,000

Start Date

September 1, 2023

Completion Date

September 1, 2024

Expected Research Outcomes & Impacts

The project intends to observe the system’s performance from its field operations with respect to its three key control objectives: (1) maximizing the freeway’s throughput under the optimized ramp metering rate; (2) preventing ramp queues from spilling over to its neighboring arterial; and (3) mitigating the potential mutual impedance between the arterial’s through traffic and its turning-flows to the ramp with the coordinated signal timings, variable phase sequences, and progression offsets. 

Prior to use in practice, new control technology or systems must go through extensive tests, using field data feedback from target deployment locations for any necessary enhancements or refinements. With the results from this study, the AF-Ramp can certainly evolve its status from the academic work to a well-calibrated system ready for deployment on Maryland’s highway networks.

Subject Areas

Connected and Automated Vehicle,