Transcript TAS Operation and Overview

The Technology Side of the
Sydney Coordinated Adaptive
Traffic System (SCATS)
Presented by:
Betsy Williams
TransCore
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SCATS Background
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The Roads and Traffic Authority of New South
Wales (RTA)
• Developer and primary user of SCATS
Continued innovation through user group
involvement
Extensive user base
• Effective, mature, practical system
Worldwide - over 21,000 intersections under
SCATS control in 71 installations
SCATS Worldwide System
Installations
Dublin
Waterford
Gresham
Park City
Menlo Park
Sunnyvale
Rzeszow
Detroit
Cobb Co
Delaware
Durham
Chula Vista
Pasco Co.
Tehran
Mashhad
Israel
Yanbu
Doha
Mexico City
Toluca
Shenyang
Shijuazhuang
Yichang Tianjin Shanghai, Ningbo
Guangzhou
Suzhou Hangzhou
Hong Kong
Manila
Dacca Hanoi
Cebu
Pattaya Vietianne
Kuala Lumpur
Brunei
Seremban
Sandakan
Singapore
Jakarta
Bandung
Suva
Fiji
Darwin
Pietermaritzburg
Concepcion
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Perth
Adelaide Sydney
Melbourne
& many other cities
Auckland
Wellington
Christchurch + 11
cities
SCATS US Installations
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Benefits of SCATS
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Reduces need/effort for updating signal
timing
Accommodates traffic fluctuations
Allow special functions to be installed for
event centers
Assist maintenance of signals via monitoring
features
Collect volume counts for planning purposes
Typical Adaptive vs. TOD Graph
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SCATS Objectives
Select cycle length, splits and offsets to achieve
• Minimum stops with light demand
• Minimum delay with normal demand
• Maximum throughput with heavy demand
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SCATS Detection
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SCATS Detection Requirements
YES
• Stop bar
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NO
• Advanced
• Upstream
• Downstream
• Mid-block
SCATS Detector Requirements
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Presence detection
Optimal strategic SCATS detectors are 6 ft x
15 ft located at the stop line for all lanes
Detectors can be longer or shorter if needed,
however shorter is better than longer
Local actuation detectors may be used at
minor intersections and can be varying in size
Typical Detector Layout
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SCATS Detectors
• SCATS operates by looking at “space”
between vehicles
• Eliminates vehicle length from equation
• Graph is linear with no double curves
Loop
Space Time (secs)
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SCATS Equipment
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SCATS Controllers
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SCATS uses 2070 controllers
• 2070 Lite – no VME backplane
• Eagle and Econolite 2070s
• 2070N – reuse of existing cabinets
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Eagle M-50 series
170 E controllers
• SafeTran or McCain controllers
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Hardware Requirements
Server Requirements
• Minimum 400 MHz Intel processor – 128M
RAM
• Windows NT or 2000
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Laptop and Workstation Requirements
• Minimum 400 MHz Intel processor – 128M
RAM
• Windows NT, XP or 2000
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Dial-in access
• 56K modem
• VPN access
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Communications
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Leased line, twisted pair copper, fiber optic,
spread spectrum radio
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300 bps per controller
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Point-to-point communication
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Point-to-multipoint communication
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Ethernet/IP communications
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SCATS Operation
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SCATS Modes
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Adaptive Mode
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Time-of-Day Mode
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Vehicle actuated operation
Master Free Mode
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Fixed-time coordination fallback mode
Free Mode
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Traffic adaptive coordination mode
Vehicle actuated with SCATS calculated splits
Flash
SCATS GUI
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Familiar Windows
interface
• Pull down menus
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Real-time
information
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Active Time-Space Monitor
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Reports
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For additional information contact:
Betsy Williams
TransCore
(770) 293-1920
[email protected]
or
Travis White
TransCore
(801) 293-1920
[email protected]
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Proven Performance
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Chula Vista, CA
• Travel Time Reduced By Up To 15%
• Travel Speed Increased By Up To 18%
• Delay Reduced By Up To 43%
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Menlo Park, CA
• Stops Reduced By Up To 24%
• Travel Time Reduced By Up To 28%
• Delay Reduced By Up To 44%
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Proven Performance
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Road Commission For Oakland County, Michigan
• Corridor Travel-Time Reduction Range 6.56% To
31.8%
• Average Travel-Time Improvement 7.8% For Peak
Traffic During Peak Periods
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Broward County, Florida
• Stops Reduced By Up To 28%
• Travel Time Reduced By Up To 20%
• Delay Reduced By Up To 42%
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SCATS Functions CYCLE LENGTH
• Automatically calculated to try to
maintain Degree of Saturation
between 80% and 90% on the lane
with the highest DS
• Lower and upper limits are user
definable
(20 secs to 190 secs)
• Can vary by up to 21 seconds per
cycle – usually only 2 to 5 seconds
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SCATS Functions - SPLITS
• Varied automatically by up to 4%
each cycle.
• Tries to maintain equal Degree of
Saturation on competing
approaches.
• Minimums are user definable.
• Maximums are limited by cycle
length and minimum requirements
of other phases.
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SCATS Functions - Linking
• Intersections can "marry" or "divorce " with each other
• Married intersections operate on a common cycle length
(and offset plan)
• Intersections marry:
• when their CL's are within 10 sec or
• when one-way volume exceeds a configured
threshold or
• when a “forced” / continuous “marriage” is
required
SS 2
SS 1
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SYSTEM
SS 3
SCATS Functions –
OFFSETS
• The best offsets are selected for the high
flow movements.
• Preset offset plans automatically vary to
compensate for varying cycle lengths.
• Directional bias based on measured
flows.
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Intersection Display
Currently
activated
detectors
shown blue.
Shown red if
faulty
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Alarm Display
All operator
actions and
alarms can be
sorted, filtered
and printed
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