ITSWC 2011Adaptive traffic control – Modelling Performance Gains for Future DevelopmentPrepared 2 / Oct / 2011

By Steven Shaw

RTA and SCATS

Roads and Traffic Authority of NSW (RTA) •manages most motorways and arterial roads across NSW•~4000 SCATS signal controlled sites.

SCATS is an area wide traffic management system •developed by the RTA.

SCATS implements adaptive traffic signal control •also fixed time plans, if required.

SCATS – 25 countries and 155 cities around the world.

Recent published SCATS papers

17th World Congress on Intelligent Transport Systems 2010, Busan, Korea1. “Introduction to experimental design when operating SCATS in simulation”

Australasian Transport Research Forum 2011, Adelaide, Australia2. “The evolution of the SCATS and the environment study”3. “The SCATS and the environment study: introduction and preliminary

results”

18th World Congress on Intelligent Transport Systems 2011, Orlando, U.S.A.

4. “Experimental design when operating SCATS in simulation: a second iteration”

5. “Validating the realism and representation of SCATS when operating in simulation”

6. “SCATS and the environment study: an introduction”

SCATS and the environment study

RTA has embarked on a comprehensive analysis study.

Stimulus for study•2009 UN Climate Change Conference in Copenhagen, Denmark

Landmark demonstration•traffic performance•production adaptive traffic control system / SCATS

Unique in public (or commercial?) space•to presenter’s knowledge

Stimulus for SatE study

SCATS and the environment study•“SatE study”

Aim•Demonstrate the transport, environmental and economic value that

the operation of the SCATS installation provides to the people of NSW.

Requirement•rigorous and defensible study – in traffic simulation

Required•realistic and representative – to achieved real-world outcomes

How will the study / paper be used?

Will support and influence•strategic traffic / transport investments•arguments for automated / adaptive traffic control•arguments for SCATS•arguments for investment in transport modelling quality•transport modelling – techniques, strategies and investments

•traffic measurement – techniques, strategies and investments

What is the study methodology?

Operate SCATS within a commercial traffic simulator- SCATSIM (AIMSUN, Commuter*, Q-Paramics*, S-Paramics, VISSIM)- ensures realistic operation- provisions representative operation

24 hour model 0300-0300 (25/11/2009)•start end model – lowest network intensity

Study scenarios – to show SCATS value

1. Base scenario • adaptive traffic control operation (Masterlink mode)• actual SCATS mode used• calibrated to real-world traffic observations• calibrating: detectors, electronic tag (inbound), bus GPS• validated to real-world operation

2. Contrary scenario• same conditions as base• differs only by SCATS Fallback mode • Fallback not used on day but would if comms failure occurred• scenario not unlike a “sophisticated fixed time system”

SCATS screen shot

SCATS screen-shotshowing intersectionMilitary Road /Spit Road intersection atMosman.

Traffic simulator screen shot

Commuter screen-shotshowing pedestrians andbuses.

Discussion of results of SatE study

Preliminary results have shown dramatic traffic performance improvement over 24 hour model:

•37% decrease in total travel time•21% decrease in total stops•6% decrease in total CO2 emissions•5% decrease in total NO emissions•10% decrease in total PM10 emissions

Traffic performance > expectations.Environmental improvement = expectations (other published

work).Adaptive control far superior to semi-adaptive, fixed time.Study defensibly demonstrates value that adaptive control

provides cities.

SCATS future

Ongoing improvements to SCATS •will increase traffic performance.

SatE study SCATSIM test bed •will allow RTA to increase the performance of NSW SCATS by optimising SCATS configuration.

SCATS flexibility empowers SCATS Engineer ability•provisions “ITS innovation” that is limited only by available traffic measurements and traffic engineer’s imagination!

SCATS innovation

In Sydney• SCATS tracks buses in real-time using GPS• SCATS prioritises buses for dynamic priority• SCATS reschedules traffic signals for selected buses• to match green times for bus arrivals – in real-time.

Did you know:SCATS can use any detector types and detector locations?SCATS provides traffic control: intersections, ramp metering, etc.SCATS allows the traffic engineer to provide customised routines?Real SCATS and configuration can be operated within traffic

simulation?

Thankyou

steven_shaw@rta.nsw.gov.au

www.scats.com.au

SCATShelp@rta.nsw.gov.au