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A new study led by Miguel Figliozzi of Portland State University provides a microscopic evaluation of how two advanced traffic control technologies work together.

Powell Boulevard, an east-west arterial corridor in southeast Portland, Oregon, has been the focus of several research studies by Figliozzi’s TTP research lab. The street is a key route for public transit buses as well as pedestrians and cars, but heavy traffic at peak hours often results in delays.

On Powell there are two systems operating concurrently: a demand-responsive traffic signal system called Sydney Coordinated Adaptive Traffic System (SCATS) and a Transit Signal Priority (TSP) system. The TSP in the Portland metro region is designed to give priority to late buses and to boost transit performance.

In previous studies Figliozzi’s lab has analyzed a multitude of factors on Powell Boulevard including traffic congestion, transit times, air quality and cyclists’ intake of air pollutants, and a before/after evaluation of SCATS.

For this study, the researchers used a novel approach to evaluate how well SCATS and TSP work together by integrating three major data sources and video recordings at individual intersections.

Figliozzi’s team worked closely with TriMet and the City of Portland to...

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An OTREC project recently took an in-depth look at the travel-time and health-related effects of a new implementation of a state of the art adaptive traffic system.

Southeast Powell Boulevard is a multimodal urban corridor connecting highway US-26 through Portland, Oregon. The corridor is highly congested during morning and evening peak traffic hours. In October 2011, an adaptive traffic system called SCATS was deployed.

The primary function of SCATS, or Sydney Coordinated Adaptive Traffic System, is to mitigate traffic congestion. Using sensors (usually inductive loops) at each traffic signal, the system tries to find the best cycle time and phasing along the corridor as traffic demand patterns change.

In this integrated multimodal study, OTREC researchers looked at the corridor’s traffic speed and transit reliability, before and after the implementation of SCATS. In addition, a novel contribution of this study was to study the link between signal timing and air quality.

To determine the impact of SCATS on traffic and transit performance, researchers established and measured performance measures before and after SCATS. The researchers used data provided by TriMet, Portland's transit authority, to compare transit times before and after SCATS as well as traffic volume data from two Wavetronix units that were installed by the City of Portland; these units collect traffic counts, speeds and classifications. For the air quality study, TriMet also...

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