Adaptive Signals 101

Outline
 Example of systems & definition
 How did Sain get involved?
 Scan Tour & ALDOT’s reaction
 How it works
 Different systems
 Graphs
 Status of ALDOT Projects

JAN 24 2012 INTRO TO ADAPTIVE SIGNAL CONTROL 2

Example of Systems
 InSync
 SCATS
 SCOOT
 ACS Lite
 Several others…


Definition
 Traffic signal timing control technology
that has the ability to utilize real-time
traffic information to adjust traffic signal
system timings in an effort to reduce
congestion and delay.


How did we get involved?
 FHWA Every Day Counts (EDC)
 EDC is designed to identify and deploy
innovation aimed at shortening project delivery,
enhancing the safety of our roadways, and
protecting the environment.

 Adaptive Signal Control Subcommittee
 Members consist of ALDOT, FHWA, City of
Montgomery, and Sain Associates
 Sain is the only consultant on the committee!


Committee Members
 FHWA
 Jeff Dogan
 ALDOT
 Stacey Glass, Gary Moore, Kim Norton,
Robert Blankenship
 City of Montgomery
 Bubba Bowden, Tim Foster
 Sain Associates
 Jeff Stephenson


Scan Tour: Sep. 12-14
2011
 Visited 3 locations in GA
 (1) City of Alpharetta
3 1
○ Tested InSync, SCOOT 2

 (2) Columbia County
○ Running InSync
 (3) Cobb County
○ Running SCATS

 Group recommended SCATS to ALDOT
front office for initial implementation in AL


ALDOT Initial
Implementation
 (1) Montgomery
 Southern Boulevard/Eastern Boulevard

 (2) Birmingham area
 US-280 3

2

1
 (3) Huntsville
 Governors Drive


Signal Timing Methods
 Free/Isolated
 Time Based Coordination
 Traffic Responsive
 Adaptive Control


Adaptive Control – How?
 The tactics of different systems work
different ways, however…
 The general idea is that data being
collected by the vehicle detectors is
being used in real time to determine the
signal timings.
 Wide range of % reductions in delay
reported by various adaptive signal
controls


SCOOT
 Split Cycle Offset Optimization Technique
 Used worldwide, a lot in Great Britain
 Uses data from advance detectors, models
progression from detector to stopline
 Factors for queuing
 Central server and on-street firmware
 Requires communication
 Need computer programming background
to understand system commands required
to operate and maintain the system


InSync
 Rhythm Engineering
 Plug-and-play
 Controller set in free mode using
existing firmware
 Detector data taken, analyzed, and
sends calls to controller
 Requires communication
 Newer program, still customizing on the
fly to meet customers needs


SCATS
 Sydney Coordinated Adaptive Traffic System
 Originated in Australia, found worldwide,
about 1/3 are in Australia
 Uses stopline video detection (6 x 15 zones)
to detect/measure gaps
 Central server selects pre-determined
cycle/split/offsets
 Communication required
 Synchro still needed!


SCATS (Cont’d)
 Certain models of controller are required to
run SCATS
 US-280 getting Eagle M50 model
 Governors Drive getting 2070
 SCATS firmware installs alongside
traditional firmware on street controller
 Any mode of detection works, but video is
recommended
 Engineering design element of project is
generally required for implementation of
equipment modifications


“Never retimed” to
“Adaptive”


“Retimed” to “Adaptive”


Savings


Adaptive vs. TOD
140

120

100

80
Adaptive Cycle
60 TOD Cycle
40

20

0
12 2 4 6 8 10 12 2 4 6 8 10 12


ALDOT Project Status
 Montgomery
 PS&E held Jan 4
 May 25 2012 Project Letting
 Birmingham
 PS&E is Jan 26
 Huntsville
 PS&E TBD (Feb 8 or Feb 9)

 ALDOT Transportation Director wants all
implemented by June 2012


Adaptive Signals 101

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