1 Adaptive Control Software – Lite (ACS-Lite) Eddie Curtis, P.E. FHWA Resource Center / HOTM NTOC Webcast March 27, 2008

2 Agenda Speaker Introductions Overview of traffic signal operations & Application of Adaptive Systems (Eddie Curtis) –State of the Practice –Traditional methods –What does Adaptive control offer –Goals and Objectives of ACS-Lite (Federal Perspective) ACS-Lite (Steve Shelby) –System Development –System Architecture –Functionality Tyler, Texas ACS-Lite Experience (Kirk Houser) –Description of deployment site –Objectives –Lessons Learned

3 Speakers Eddie Curtis, P.E. Traffic Management Specialist, FHWA Office of Operation / Resource Center Steve Shelby, PhD Research Projects Manager Siemens Energy & Automation, Inc. Process Solutions Division (PSD) Business Unit Intelligent Transportation Systems Kirk Houser, P.E. City Traffic Engineer City of Tyler, Texas

4 Purpose of Traffic Signals Moving traffic in an orderly fashion; Minimizing delay to vehicles and pedestrians; Reducing crash-producing conflicts Maximizing the capacity of each intersection approach

5 The State of Traffic Signal Operations

The Issues D- D C- F C 6 6

7 Which agencies are having the greatest difficulty F DD D C

8 How is your signal system performing? There is no national standard of performance. Phone calls are frequently used as a measure; Before and After studies are relative measures; Reporting

9 What could you do with Performance information? Proactively Manage –Identify need for improvements –Identify gaps –Prioritize resources

10 Traffic signals compete for resources

U.S. National Crash Characteristics Crash Type Total CrashesFatalities + Injuries NumberPercentNumberPercent Non-Intersection3,599,00057%1,022,54952% Unsignalized Intersection 1,418,00022%481,99425% Signalized Intersections**** 1,299,00021%462,76623% Total6,316,000100%1,967,309100% Source: Adapted from Table 28 of Traffic Safety Facts (4)

12 Improve Safety –Can improving signal operations enhance intersection safety. –Do poor signal operations contribute to intersection crashes. Reduce Congestion The connection between operations and safety

13 Signal Timing measures that reduce crashes Provide progression –Time based coordination –Interconnect traffic signals –Centrally manage –Optimize offsets Optimization of signal timing –Retiming –Optimize phase splits Modify clearance intervals –Dilemma zone protection Provide Green Extension Advanced detection

14 Recent activities

Improving Traffic Signal Operations 1975 Delay and Fuel consumption at traffic signals, Kenneth Courage,University of Florida, (One Billion gallons of fuel) 1983 Traffic signal timing optimization, achieving national objectives through state and local government actions, Gary Euler, FHWA (Two Billion gallons of fuel, benefit/cost 63:1) 2004 The benefits of retiming traffic signals, Srinivasa Sunkari, TTI »(MDDOT 215 INTS, 94% reduction in delay, 77% reduction in stops) »(San Jose 25 INTS, 35% reduction in delay, 39% reduction in stops) 2005 / 2007 NTOC Traffic Signal Report Card (D- / D) »(300 million vehicle hours of delay, major roadways, benefit/cost 40:1)

Traffic Signal Control Evolution

17 Benefits of Adaptive Signal Timing Responsive to traffic conditions –Reduce traffic delay –Delays onset of saturated conditions Reduces or eliminates the need to retime traffic signals –$1800 – $3500 / intersection Improvements over Time Of Day plans –Travel time –Delay –Stops –Fuel consumption Data collection and archiving

18 Signal Timing Design Design Period

19 The Signal Timing Process Trigger Event (Phone Call / Scheduled Retiming) Identify Intersection Collect organize existing data Conduct site survey Obtain Turning Movement data Calculate local timing parameters Group signals Calculate coordination parameters Install and evaluate new plans

20 Is the data were collecting significant? Utilize peak 15 min day for 4 time periods AM, Mid-Day, PM, Off-peak 15hr/day X 5day/wk X 52wk/yr X 3yr = 11,720 hrs.0085 %

21 Prolong the effectiveness of Signal Timing 0 5% 10% 15% 20% 25% Time in YEARS Prolongs the effectiveness of Signal Timing Source: ITS Siemens Adaptive

Adaptive Control Deployment

Currently Deployed Adaptive Systems SYSTEM (# of Intersections) SCATS 6 SCOOT 1 OPAC 2 RHODES 3 ATCS 4 Other 5 Total Intersections TOTAL PERCENT OF MARKET SHARE 45.19%9.63%3.09%2.04%37.71%2.34%

24 Disadvantages High capital cost $$$ Requires extensive calibration & monitoring Requires active maintenance of traffic detectors Communications overhead More technical staffing Oversaturated conditions

25

26 FHWA Goals for ACS-Lite Low cost Leverage existing infrastructure Retrofit with existing controllers Fully actuated detector layout Typical communications Closed Loop systems » 20,000 Systems Provide improvements over typical TOD timing Operate without connectivity to a TMC Closed loop field master architecture Use NTCIP

27 Benefits of ACS-Lite

28 Private Sector Partners

29 Integration Sites & Deployment Gahanna, OH (Econolite) Bradenton, FL (PEEK) El Cajon, CA (McCain) Houston, TX (EAGLE) Tyler, TX November 07

30 ACS-Lite Benefits

31 Questions ???? Eddie Curtis, P.E. Traffic Management Specialist Phone: (404)