1 The Technology Side of the Sydney Coordinated Adaptive Traffic System (SCATS) Presented by: Betsy Williams TransCore.

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The Technology Side of the Sydney Coordinated Adaptive

Traffic System (SCATS)

Presented by:Betsy Williams

TransCore

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SCATS Background

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

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Shenyang

Tianjin Shanghai, NingboSuzhou HangzhouGuangzhou

Hong KongManilaCebu

Kuala LumpurSerembanSingapore

BruneiSandakan

JakartaBandung

Detroit

DelawareDurham

Cobb Co

Suva Fiji

Shijuazhuang

TehranMashhad

Dublin

Auckland Wellington Christchurch + 11 cities

Darwin

Perth Adelaide Sydney Melbourne & many other cities

Mexico CityToluca

SCATS Worldwide System Installations

YichangYichangDoha

Chula VistaPasco Co.

Concepcion

GreshamPark CityMenlo ParkSunnyvale

Waterford

IsraelYanbu

Dacca HanoiPattaya Vietianne

Rzeszow

Pietermaritzburg

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SCATS US Installations

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Benefits of SCATS

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

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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

NO

• Advanced

• Upstream

• Downstream

• Mid-block

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SCATS Detector Requirements

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

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Typical Detector Layout

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• SCATS operates by looking at “space” between vehicles

• Eliminates vehicle length from equation

• Graph is linear with no double curves

LoopSpace Time (secs)

SCATS Detectors

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SCATS Equipment

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SCATS Controllers

SCATS uses 2070 controllers• 2070 Lite – no VME backplane• Eagle and Econolite 2070s• 2070N – reuse of existing cabinets

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

Laptop and Workstation Requirements• Minimum 400 MHz Intel processor – 128M RAM• Windows NT, XP or 2000

Dial-in access• 56K modem

• VPN access

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Communications

Leased line, twisted pair copper, fiber optic, spread spectrum radio

300 bps per controller

Point-to-point communication

Point-to-multipoint communication

Ethernet/IP communications

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SCATS Operation

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SCATS Modes

Adaptive Mode Traffic adaptive coordination mode

Time-of-Day Mode Fixed-time coordination fallback mode

Free Mode Vehicle actuated operation

Master Free Mode Vehicle actuated with SCATS calculated splits

Flash

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SCATS GUI

Familiar Windows interface• Pull down menus

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) [email protected]

or

Travis White TransCore

(801) [email protected]

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Proven Performance

Chula Vista, CA• Travel Time Reduced By Up To 15%• Travel Speed Increased By Up To 18%• Delay Reduced By Up To 43%

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

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

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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• 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

SCATS Functions - CYCLE LENGTH

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• 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.

SCATS Functions - SPLITS

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SS 1

SS 2 SS 3

SYSTEM

• 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

SCATS Functions - Linking

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• 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.

SCATS Functions – OFFSETS

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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