USDOT Congestion Initiative Focus on Traffic Signal Timing
USDOT is committed to helping State and local agencies improve their traffic signal management programs. One effort is the traffic signal operation self-assessment, which encourages agencies to take a serious look at how traffic signal systems are being managed within their jurisdiction. The self-assessment provides the input to develop the National Traffic Signal Report Card, part of a national effort to bring more attention to the need for additional investment in traffic signal operations.
The first National Traffic Signal Report Card was released in 2005 and received extensive media attention. The national score was D-, and media coverage focused on the need for additional resources to support traffic signal operation. Then Washington, DC Mayor Anthony A. Williams commented that "this report card on traffic signal timing should be a wake-up call for all mayors. In DC, we are updating our signals and timing to improve traffic flow and to lessen congestion."
The emphasis of the report card is on communicating the importance of high-quality operations, improved training, and management programs that produce traffic signal timing that corresponds to current traffic patterns, thus facilitating traffic flow and lessening the opportunity for congestion. Development of the 2nd National Traffic Signal Report Card is underway for release in late summer 2007.
A tool to help improve signal timing is ACS (Adaptive Control Software) Lite (ACS-Lite), a product developed through a public-private partnership of FHWA, private sector researchers, and traffic signal controller manufactures. ACS-Lite is designed to monitor and evaluate traffic operations and refine signal timing consistent with current traffic conditions in real time. ACS-Lite is intended to be a low-cost solution for improving signal timing in small- to medium- size communities. The software is designed specifically for closed-loop traffic signal systems, which represent an estimated 90 percent or more of U.S. traffic signal systems. ACS-Lite is being aggressively promoted by the Federal Highway Administration.