1 adaptive control software – lite (acs-lite) eddie curtis, p.e. fhwa resource center / hotm ntoc...
TRANSCRIPT
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Adaptive Control Software – Lite (ACS-Lite)
Eddie Curtis, P.E.
FHWA Resource Center / HOTM
NTOC Webcast
March 27, 2008
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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
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Speakers
Eddie Curtis, P.E.Traffic Management Specialist, FHWAOffice of Operation / Resource Center
Steve Shelby, PhDResearch Projects ManagerSiemens Energy & Automation, Inc.Process Solutions Division (PSD)Business Unit Intelligent Transportation [email protected]
Kirk Houser, P.E.City Traffic EngineerCity of Tyler, [email protected]
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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
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The State of Traffic Signal Operations
The Issues
D-D
C-
FC-
C
6 6
7
Which agencies are having the greatest difficulty
5351
65 67 65 67 6671
6669
30
35
40
45
50
55
60
65
70
75
Less Than < 50signals
50 to 150signals
150 to 450signals
450 to 1000signals
More Than1000 signals
Score by System Size
2005 Score 2007 Score
F
D D DC
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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
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What could you do with Performance information?
• Proactively Manage
– Identify need for improvements
– Identify gaps
– Prioritize resources
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Traffic signals compete for resources
U.S. National Crash Characteristics
Crash Type Total Crashes Fatalities + Injuries
Number Percent Number Percent
Non-Intersection 3,599,000 57% 1,022,549 52%
Unsignalized Intersection
1,418,000 22% 481,994 25%
Signalized Intersections****
1,299,000 21% 462,766 23%
Total 6,316,000 100% 1,967,309 100%
Source: Adapted from Table 28 of Traffic Safety Facts 2002. (4)
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• 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
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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
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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
Late 1960sMid to Late
1980s Mid 1990s 2000
Open Loop SystemWith TrafficDetection
Closed Loop ControlCentral
Timing Plan selection byField Master
Closed LoopAdaptive Control
Timing Plan selection byField Master (ACS-Lite)
Centralized Control
UTCSCentral Control
Interval or Phase Control
Traffic Responsive /Adaptive Control
SCATSSCOOTATCS
Adaptive Control
RHODESOPAC
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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
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Signal Timing Design
0500
1000150020002500300035004000
12:00AM
2:00AM
4:00AM
6:00AM
8:00AM
10:00AM
12:00PM
2:00PM
4:00PM
6:00PM
8:00PM
10:00PM
Time of Day
VP
H (
veh
icle
s p
er h
ou
r)
Design Period
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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
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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 %
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Prolong the effectiveness of Signal Timing
0
5%
10%
15%
20%
25%
1 2 4 53
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 906 193 62 41 756 472005
PERCENT OF MARKET SHARE 45.19% 9.63% 3.09% 2.04% 37.71% 2.34%
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Disadvantages
• High capital cost $$$
• Requires extensive calibration &
monitoring
• Requires active maintenance of
traffic detectors
• Communications overhead
• More technical staffing
• Oversaturated conditions
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Cost Performance
Proactive Management
Data
Typical Existing Systems
Cost
Performance
Proactive Management
Data
Typical Adaptive Systems
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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
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Benefits of ACS-Lite
Cost
Performance
Proactive Management
Data
ACS-Lite
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Private Sector Partners
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Integration Sites & Deployment
Gahanna, OH(Econolite)
Bradenton, FL(PEEK)
El Cajon, CA(McCain)
Houston, TX(EAGLE)
Tyler, TX November 07
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ACS-Lite Benefits
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Questions ????
Eddie Curtis, P.E.
Traffic Management Specialist
Phone: (404) 562-3920