Adaptive Traffic Controller Systems in America

[tradephoric]

Adaptive Traffic Controller Systems (ATCSs) are slowly gaining popularity in America.  These systems don't rely on fixed time-of-day plans but instead adaptively adjust the signal timings each cycle based on the current detection at the intersection or group of intersections.  The 7 most commonly used ATCSs in America are the following:

ACS Lite:  FHWA initiated development of Adaptive Control Software Lite (ACS Lite), prescribing a lower cost and more easily managed system, to surmount the major deployment impediments and bring this rarely used state-of-the art technology to the mainstream.  ACS Lite offers significant cost savings relative to earlier FHWA-sponsored adaptive systems by better leveraging existing infrastructure

InSync:  An adaptive traffic signal system developed by Rhythm Engineering (Lenexa, Kansas) that uses innovative sensor technology, image processing, and artificial intelligence. These elements are integrated into a system that automatically optimizes local traffic signals and coordinates signals along roadway arterials according to real-time traffic demand. The use of InSync eliminates the need for static signal coordination plans.

LA ATCS:  The Adaptive Traffic Control System (ATCS), developed by Los Angeles Department of Transportation (LA DOT), was first deployed as a part of the Automated Traffic Surveillance and Control (ATSAC) Center in 1984 for the Los Angeles Olympic Games.

OPAC:  The Optimized Policies for Adaptive Control (OPAC) strategy is a real-time signal timing optimization algorithm, which was originally developed at the University of Massachusetts.  OPAC is a distributed control strategy featuring a dynamic optimization algorithm that calculates signal timings to minimize a performance function of total intersection delay and stops.

RHODES:  The basic concept behind the RHODES strategy and algorithms is to set signal phasing that proactively responds to stochastic variations in traffic flow. This requires (1) the identification of various traffic objects at different levels of aggregation–individual vehicles, platoons of vehicles, and overall traffic flow in terms of vehicles per minute; (2) the identification of their natural dynamics and responsiveness to signal control; and (3) setting phase durations to allow these traffic objects to move according to their objective.

SCATS:  The Sydney Coordinated Adaptive Traffic System (SCATS)
is an Area Traffic Control (ATC) or Urban Traffic Control (UTC) system consisting of hardware, software, and a unique traffic control philosophy that operates in real time; adjusting signal timings in response to variations in traffic demand and system capacity as they occur. Rather than changing individual intersections in isolation, SCATS manages groups of intersections that are called "subsystems,"  the basic unit of the system. Each subsystem will consist of a number of intersections, usually between one and ten. One of those intersections is designated as the controlling or "critical"  intersection.

SCOOT:  In SCOOT optimization of traffic control in the network is achieved using small, regular changes in signal timings designed to avoid major disturbance of traffic flow. Loop detectors are polled by the controller for occupancy every one-quarter second and typically transmitted once per second to the central computer, although the latest version of SCOOT relaxes this requirement.


According to the FHWA there are some 272,000 traffic signals in America and of those roughly 4,700 are adaptively controlled.  Although there are a lot of cities that have begun experimenting with adaptive systems many are just test beds.  Some of the largest systems being deployed include:

Los Angeles — 3,000 signals
Oakland County (Metro Detroit) — 650 signals
Minneapolis, MN — 127 signals
Cobb County (Metro Atlanta) — 74 signals

I put together a Google .KMZ that show all the cities in the USA (and parts of Canada) that has deployed some type of adaptive signal system.  Let me know if there are areas that I have missed.
http://www.mediafire.com/?os4k1u5nxxni2v1

Also, the NCHRP wrote a paper titled "Adaptive Traffic Control Systems: Domestic and Foreign State of Practice (2010)" .  A lot of the info i used was from there.

[M3019C LPS20]

There is somewhat of a similar system that exists within the city of New York. In the 1990s, the establishment of T.M.C. (A.K.A. Traffic Management Center) in Manhattan led to the connection between the center and most, if not all, of its signal controllers, which were at the time electro-mechanical. The outer boroughs, on the other hand, were connected to a center in Queens I believe. With an electro-mechanical signal controller, your options are rather limited, simply due to the nature of it. Many were (still are as well) controlled by computer systems that are commonly known as "blue boxes." The system was wired to the signal controller, and it was completely under the systems operation. The signal controller worked on its own if the computer system's power was lost. This system has several interesting features, such as pre-emption, interconnection, detection. Some of these were not in use, and the main purpose was to provide ample time lengths to the signal controller (for only cycles).

As time progressed, though, New York City first began to experiment with the A.S.T.C., which is also known as the advanced solid state traffic controller. It was first in use in the late 1990s, and, by the early 2000s, the city was in favor of it. Since then, the city has replaced most of its original signal controllers. The city is still in the process of the conversion. With this new signal controller, the folks at the center are able to communicate with it 24/7, which is beneficial in many ways. If a malfunction occurs, the problem is immediately detected by the center. D.O.T. repairs it within a matter of hours. The center could also adjust the time lengths of cycles and signal intervals (if necessary) to meet current status of traffic. Many tricks up their sleeves, really (if that is a simple way to put it).

Once the conversion is completed, all of New York City's signalized intersections will be controlled by the center in lower Manhattan. That's the main goal as of now.

Roughly speaking, there are 12,500 signalized intersections in the entire city of New York. Out of all of them, about 6,000 have been successfully converted. The others are still controlled by electro-mechanical signal controllers.

Out of all of the five boroughs, Staten Island is the only borough that has been totally converted from electro-mechanical signal controllers to computerized signal controllers, since it is the only borough in the city that has the least amount of signalized intersections. I'd say roughly 568 exist on the island as of present day.