Total crashes per mile per year decreased by 28.84 percent on a corridor operating under SCATS adaptive signal control in Oakland County, Michigan.

Experience with Sydney Coordinated Adaptive Traffic Systems (SCATS) in Oakland County, Michigan.

September 2010
M-59 Corridor,Detroit,Michigan,United States

Summary Information

This study examined the safety effectiveness of Sydney Coordinated Adaptive Traffic Systems (SCATS) on a six mile segment of M-59 in the northern metropolitan area of Detroit, Michigan. In addition to a before and after analysis, researchers compared performance on M-59 to a similar corridor (Dixie Highway) having only pre-timed signal control.

SCATS was initially deployed at 28 intersections and then expanded through Oakland County's traffic control system, Faster and Safer Travel through Traffic Routing and Advanced Controls (FAST-TRAC). The design was intended to use roadside video cameras, computers, and communication networks to monitor traffic conditions and automatically adjust signal timing as needed to reduce vehicle stops, decrease delay, and improve traffic flow. After the initial deployment, engineers continued to fine tune SCATS to improve traffic conditions and increase safety.

In 2007, a study was conducted on M-59 to evaluate the performance of SCATS in terms of mobility benefits. Initial results showed that after the system was initially installed the number of vehicle stops on the corridor decreased significantly. Benefits for other measures, however, were marginal. To gain a better understanding of the impacts on safety, researchers conducted additional analysis on the following crash data.
  • Crash data of 1999-2001 (before period) and 2003-2008 (after period) on M-59.
  • Crash data of Dixie Highway (pre-timed corridor) and M-59 (SCATS corridor) during 2003-2008.

On average, after SCATS was installed.
  • Total crashes per mile per year decreased by 28.84 percent between 1999-2001 and 2003-2008.
  • Between these two periods: Type A crash severity (incapacitating injury, permanent injury) decreased 48.8 percent per year per mile, Type B crash severity (non incapacitating injury, temporary injury) decreased 51.13 percent per year per mile , and Type C crash severity (possible injury, slight bruises and cuts) decreased 36.36 percent per year per mile.
  • Property damage only (PDO) crash type decreased by 24.58 percent per year per mile.
  • Following the national trend the crash rate of this corridor also decreased.
Although SCATS was more expensive to install and maintain compared to pre-timed signals, and its mobility benefits were marginal in some cases, SCATS was effective at reducing the number of vehicle stops on the corridor. Crash severity transitioned from Type A and Type B crashes to Type C crashes, improving safety, and providing a cost savings to the traveling public.

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Safety Evaluation of SCATS Control System: Final Report

Author: Dutta, Utpal; Deb McAvoy; Jim Lynch; and Laurel Vandeputte

Published By: University of Detroit Mercy

Source Date: September 2010

Other Reference Number: Report No: MIOH UTC TS22p1-2 2010-Final



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Goal Areas


Typical Deployment Locations

Metropolitan Areas


traffic signals, adaptive signals

Benefit ID: 2013-00831