TxDOT Research Library - TxDOT Research Project

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Operational Analysis of Active Traffic Management Strategies

Project Summary

This project will develop tools for analyzing the effectiveness of active traffic management (ATM) strategies, along with supporting methodologies. The ATM strategies studied in this project are ramp metering, variable speed limits, mainline gap metering, coordinated freeway-arterial operations, dynamic lane use control, dynamic shoulder lane (hard shoulder running), dynamic route guidance, junction control, travel time signs, overhead gantries. and queue warning. The supporting methodologies will predict the effectiveness of these strategies based on traffic and other network data. These tools and methodologies address three related needs: using traffic data to perform bottleneck analyses; identifying locations where ATM implementation would relieve congestion; and -identifying ATM decision rules to be applied in real-time. Including activation/deactivation thresholds and control rules. The project approach is informed by the following principles: Multiple tools are needed to accommodate differences in data availability at various locations, as well as the availability of already-calibrated simulation and assignment models for other purposes. A “one size fits all” approach is insufficient. Bottlenecks are a property of a system, not a single facility. A network-based approach is needed to connect local improvements in traffic flow to broader congestion measures. Properly evaluating the long-term effects of ATM requires accounting for changes in habitual driving behavior. Improving flow along a corridor may attract additional vehicle demand from alternate routes and can reduce the benefits of ATM in reducing congestion.

The last two factors are particularly critical, and failing to account for network effects and long-term behavior changes will systematically overestimate the benefits of ATM. The tools developed in this project incorporate these effects, accurately evaluating ATM benefits.

The research team will develop four methodologies, including supporting tools: combining microsimulation for traffic realism and dynamic traffic assignment for vehicle re-routing and bottleneck analysis, and three frameworks which require only one, or neither, of these models. For the latter frameworks, the research team will replace unavailable models with much simpler methodologies (resembling the procedures in the Highway Capacity Manual), obtained from comprehensive simulation runs performed during the project. These latter methodologies will be presented in spreadsheet form. All tools, spreadsheets. and supporting documentation will be delivered to TxDOT and a training workshop will be scheduled.

Project Number

0-6859

Status

Completed

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