Urban Traffic Management System

Task ( 2 )

Wael Saad Hameedi

P71062

KKKA 6424

INTELLIGENT URBAN TRAFFIC CONTROL

SYSTEM

Ir. Dr. Riza Atiq Abdullah O.K. Rahmat

What is task ( 2 ) about ?

Task ( 2 ) about discussing several types of systems that are needed to

implementing and improving the urban traffic management system.

Those systems are listed below :

MAXBAND

SCATs

SCOOT

ITACA

RONDO

UTOPIA

MAXBAND

� is a bandwidth optimization program that calculates signal timing plans on arterials

and triangular networks. MAXBAND produces cycle lengths, offsets, speeds, and

phased sequences to maximize a weighted sum of bandwidths. The primary advantage

of MAXBAND is the freedom to provide a range for the cycle time and speed. The

lack of incorporated bus flows and limited field tests are disadvantages of

MAXBAND.

OR

� is a portable, off-line, FORTRAN IV computer program for setting arterial signals to

achieve maximal bandwidth. Special features of the program include (a) automatically

choosing cycle time from a given range, (b) permitting the design speed to vary within

given tolerances, (c) selecting the best lead or lag pattern for left-turn phases from a

specified set, (d) allowing a queue clearance time for secondary flow accumulated

during red, (e) accepting user-specified weights for the green bands in each direction,

and (f) handling a simple network in the form of a three-artery triangular loop. Green

splits can be provided or, alternatively, flows and capacities can be given and splits

calculated by using Webster's theory. The program produces cycle time, offsets,

speeds, and order of left-turn phases to maximize the weighted combination of

bandwidths. The optimization uses Land and Powell's MPCODE branch and bound

algorithm. As many as 12 signals can be handled efficiently. The program is available

from the Federal Highway Administration.

STRUCTURE OF THE SYSTEM

Figure 2 shows the overall structure of the MAXBAND system. The system consists of five

modules: an overall control module (MAXBAND); and four modules which handle specific

subtasks (INPUT, MATGEN, MPCODE and OUTPUT). The latter four modules execute

sequentially.

Figure 2: Structure of MAXBAND System

SCATS

- How SCATS works

Intelligent traffic management

SCATS (Sydney Coordinated Adaptive Traffic System) is an adaptive urban traffic

management system that synchronizes traffic signals to optimize traffic flow across a whole

city, region or corridor.

SCATS is more than just a way of linking traffic signals to provide road management

coordination, it’s a sophisticated traffic engineering system that allows you to implement

complex, objective-oriented, traffic management strategies.

To use SCATS you need:

A SCATS-compatible Traffic Signal Controller.

A centralized computer system to manage all Traffic Signal Controllers.

A reliable communications network for the centralized computer system to exchange

data with all Traffic Signal Controllers in your city.

Vehicle detectors at each intersection, usually in the form of loops in the road

pavement.

Adaptive control

SCATS is a truly intelligent traffic management system that considers all aspects of traffic

control and can respond to the demands of the network in real time.

Intelligent control that responds to changing demands

SCATS uses an advanced coordinated signal system that considers all the key aspects of

controlling the road network to ensure optimal traffic flow.

In response to demands on the traffic network, SCATS can:

Determine stage splits at intersections

Alter cycle time of intersections either individually or in groups

Introduce cycle or plan-dependent options.

Using data from vehicle detectors and SCATS, your traffic engineer is able to implement

maximum throughput, minimum stops and minimum delay strategies. SCATS is a cycle-by-

cycle system that optimizes cycle length, splits and offsets each and every cycle.

Real-time efficiencies

The SCATS system operates in real time, adjusting signal timings in response to variations in

traffic demand. SCATS controls traffic on an area basis rather than on an individual,

uncoordinated intersection basis.

SCATS is adaptive unlike a fixed time system that is generally unable to cope with

unpredictable traffic conditions. This means it requires no pre-calculations or composite

signal timing plans.

Instead, SCATS uses logic and algorithms to analyses real-time traffic data from vehicle

detectors to produce signal timings that are suitable for the prevailing traffic conditions.

Vehicle detectors

Vehicle detectors are required to operate an efficient fully adaptive, urban traffic control

system. The detectors (typically in the form of loops) act as voting elements, which, as more

vehicles cross, help SCATS to determine the traffic conditions needed to:

Extend the green phase.

Give an approach more time.

Reduce the green phase back to normal levels.

Alternative detection technology can be used as long as it has clean contact outputs and can

be interfaced with a SCATS-compatible or SCATS-compliant controller.

What are the packages of the SCATs software:

A versatile and flexible traffic management system

The SCATS urban traffic management system is available in various packages with pricing

to suit the operator, based on their needs and budget.

Core software

SCATS Core software license is able to be purchased in a range of sizes to suit your needs

and is expandable to 16,000 intersections. It also has capabilities to produce on-screen

performance, alarm, event and incident reports.

What are the options available for this software ?

Traffic Reporter

Reports traffic volumes for any given road approach, shows the variation of the actual cycle

length time and compares this information with SCATS cycle length time requirements. This

gives the operator an understanding of how well the SCATS system is coordinating the

whole road corridor in that subsystem.

SCATS Communication Monitor

This tool helps operators evaluate the communications between the SCATS Regional

Computer and the Traffic Signal Controller at an intersection. The Communications Monitor

places emphasis on the loss of communications and loss of adaptive control due to Fallback

(the mode whereby the Traffic Signal Controller starts using plan data stored locally).

SCATS Alarm Analyser

Provides a collated report of the occurrence of faults and can specify which specific faults to

report on over a given period of time.

SCATS Alert

An automated service that’s designed to monitor particular events at one or more locations,

and notify the operator of any interruptions or occurrences.

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SCATS Action Runner

An application that can run SCATS action lists and route pre-emption plans via a simple user

interface. It can be used by staff in an ambulance station or fire station who need to activate a

pre-programmed sequencing of a range signals. It also provides real-time status monitoring

of activated plans and ability to halt activated plans.

SCATS Flexilink Data Generator

An application that generates the data that is used when the SCATS system is operating

under Flexilink mode. The use of the data enables better signal coordination during a loss of

communications and automates a task that can be very complex and time consuming when

done manually.

History Reader

An application that reads historical data collected and saved by the SCATS system and

displays the data to the operator for analysis.

And there are additional products can significantly improve the management of the

road network like :

- SCATSIM

- WinTRAFF

- TRAFFIC MANAGEMENT INFORMATION SYSTEM (TMIS)

- NGEN

Why choose SCATS?

Here are just some of the reasons why you should choose SCATS for your town or city:

Reduced costs

SCATS maximizes road network use with real-time adaptive control. Its self-

calibration system minimises manual intervention, which can reduce your traffic

management operational costs. SCATS requires no ongoing traffic surveys and

site visits to update traffic plans.

Proven performance

SCATS has proven itself in cities and towns across the globe, providing real and measurable

reductions in road travel times and delays under various road network, traffic and driving

conditions. Read more about Proven performance

.

A global traffic solution

SCATS has been in use for over 40 years and is sold in 27 countries around the world.

Highly configurable

SCATS features a wide range of configuration parameters. It is an 'Engineers toolbox' with

the power to allow engineers to reconfigure the system to meet changing traffic needs.

Flexible integration

SCATS is designed to be modular and can be integrated with a wide variety of Intelligent

Transport Systems (ITS).

Ongoing software improvements

We're regularly improving our software to meet the needs of our customers and the demands

of increasing traffic, and the evolution of traffic systems.

Owned, developed and used by the New South Wales Government, Australia

When you choose SCATS you are choosing a system that is 100% owned, developed and

used by the NSW Government of Australia for over 40 years.

SCOOT

What is SCOOT?

SCOOT is the world's leading adaptive traffic control system.

It coordinates the operation of all the traffic signals in an area to give good progression to

vehicles through the network.

Whilst coordinating all the signals, it responds intelligently and continuously as traffic flow

changes and fluctuates throughout the day. It removes the dependence of less sophisticated

systems on signal plans, which have to be expensively updated

WHY YOU NEED SCOOT ?

Traffic congestion is an ever increasing problem in towns and cities around the world and

local government authorities must continually work to maximize the efficiency of their

highway networks whilst minimizing any disruptions caused by incidents and events.

Modern traffic signal control provides an important tool in the traffic manager's toolbox for

managing the highway network and SCOOT is the world leading adaptive signal control

system that responds automatically to fluctuations in traffic flow through the use of vehicle

detectors. Many benefits are obtained from the installation of an effective Urban Traffic

Control system utilizing SCOOT, both reducing congestion and maximizing efficiency

which in turn is beneficial to the local environment and economy.

World leading adaptive control system

Customized congestion management

Reductions in delay of over 20%

Maximize network efficiency

Flexible communications architecture

Public transport priority

Traffic management

Incident detection

Vehicle emissions estimation

Comprehensive traffic information

How SCOOT works ?

Information on the physical layout of the road network and how the traffic signals control the

individual traffic streams are stored in the SCOOT database.

Any adaptive traffic control system relies upon good detection of the current conditions in

real-time to allow a quick and effective response to any changes in the current traffic

situation.

SCOOT detects vehicles at the start of each approach to every controlled intersection. It

models the progression of the traffic from the detector through the stopline, taking due

account of the state of the signals and any consequent queues.

The information from the model is used to optimise the signals to minimise the network

delay.

The Kernel software at the heart of a SCOOT system is standard to all installations. The

additional software (the "knitting" or UTC software) which links the SCOOT Kernel to on-

street equipment and which provides the user interface is specific to the supplier.

The operation of the SCOOT model is summarized in the diagram above. SCOOT obtains

information on traffic flows from detectors. As an adaptive system, SCOOT depends on

good traffic data so that it can respond to changes in flow. Detectors are normally required on

every link. Their location is important and they are usually positioned at the upstream end of

the approach link. Inductive loops are normally used, but other methods are also available.

When vehicles pass the detector, SCOOT receives the information and converts the data into

its internal units and uses them to construct "Cyclic flow profiles" for each link. The sample

profile shown in the diagram is color coded green and red according to the state of the traffic

signals when the vehicles will arrive at the stop line at normal cruise speed. Vehicles are

modeled down the link at cruise speed and join the back of the queue (if present). During the

green, vehicles discharge from the stop line at the validated saturation flow rate.

The data from the model is then used by SCOOT in three optimizers which are continuously

adapting three key traffic control parameters - the amount of green for each approach (Split),

the time between adjacent signals (Offset) and the time allowed for all approaches to a

signalled intersection (Cycle time). These three optimizers are used to continuously adapt

these parameters for all intersections in the SCOOT controlled area, minimizing wasted

green time at intersections and reducing stops and delays by synchronizing adjacent sets of

signals. This means that signal timings evolve as the traffic situation changes without any of

the harmful disruption caused by changing fixed time plans on more traditional urban traffic

control systems.

Traffic Management

Throughout its life SCOOT has been enhanced, particularly to offer an ever wider range of

traffic management tools. The traffic manager has many tools available within SCOOT to

manage traffic and meet local policy objectives such as: favoring particular routes or

movements, minimizing network delay, delaying rat runs and gating traffic in certain areas of

the city. Because of its efficient control and modeling of current conditions, SCOOT has

much more scope to manage traffic than less efficient systems. For instance, buses can be

given extra priority without unacceptable disruption to other traffic.

SCOOT detectors are positioned where they will detect queues that are in danger of blocking

upstream junctions and causing congestion to spread through the network. Within SCOOT,

the traffic manager is able to prioritise where such problems should be minimised and

SCOOT then automatically adjusts timings to manage the congestion.

Where local action is insufficient, the engineer can specify holding areas where queues

should be relocated to in critical conditions, gating traffic entering the urban area to ensure

efficient operation of critical, bottleneck links. SCOOT will continuously monitor the

sensitive area and smoothly impose restraint to hold traffic in the specified areas when

necessary.

SCOOT naturally reduces vehicle emissions by reducing delays and congestion within the

network. In addition it can be set to adjust the optimisation of the signal timings to minimise

emissions and also provide estimations of harmful emissions within the controlled area.

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WHERE SCOOT CAN BE USED ?

SCOOT was originally designed to control dense urban networks, such as large towns and

cities. It is also successful in small networks, especially for areas where traffic patterns are

unpredictable. With over 200 systems worldwide SCOOT is working effectively in a wide

range of conditions in places as diverse as big congested cities: Beijing, Bangkok and

London, to small towns or networks such as: Heathrow airport and systems localized round

individual junctions of the M25.

When junctions are some distance apart (more than about 1km) isolated junction control

using a system such as MOVA may be more appropriate. Other site-specific factors may

influence the decision on method of control.

Many cities have well defined main radial routes with many signalized junctions and few, if

any, traffic signals between the outer areas of the radials. SCOOT has been successfully used

in such cities. The areas of Birmingham and Leicester used in the emissions trials are

examples of radials controlled by SCOOT.

What System basics ?

SCOOT depends on good traffic data for successful operation and the detectors are an

essential part of the system. Inductive loops are most common, though other types of detector

can be used. For best results, detectors are required on each link. Installing inductive loops,

and maintaining them subsequently, is a significant element in the cost of SCOOT, although

less than would be required if all the junctions were operated by isolated VA. Overhead

detectors have been used successfully in some situations.

A SCOOT network is divided into "regions", each containing a number of "nodes" (signalled

junctions and pedestrian crossings) that all run at the same cycle time to allow co-ordination.

Nodes may be "double cycled" (i.e. operate at half of the regional cycle time) at pedestrian

crossings or undersaturated junctions. Region boundaries are located across links where co-

ordination is least critical, e.g. long links. Data on the regions, nodes, stages, links and

detectors will need to be stored in the SCOOT database.

When all the equipment has been installed and the network data input into the database, the

system will need to be validated. Validation of SCOOT is the process of calibrating the

SCOOT traffic model so that it reflects as accurately as possible the actual events on the

street network. This is critical, to ensure effective performance of the system. Those parts of

the system that have been validated can be operated under SCOOT control whilst further

nodes are being validated. Once the system has been validated, the traffic management

parameters can be set to manage traffic in line with the authority's strategy.

Highway authorities wishing to install a SCOOT system or to upgrade an existing one may

wish to go straight to one or both of the two traffic system companies licensed to supply

SCOOT. However, prospective users with limited experience of UTC systems may find it

useful to seek advice from a consultant with experience in the field.

An example of a results obtained from applying SCOOT system Beijing :

SCOOT version 2.3 was installed in Beijing with the capability of controlling cycle

traffic as well as motor vehicle. Previously Beijing's urban traffic control was

uncoordinated. A survey was carried out by the Beijing Research Institute of Traffic

Engineering (BRITE) to assess the benefits of this SCOOT system. The results were as

follows:

Time of day % Reduction using SCOOT (average on all routes)

Journey time Delay (stopped time) Stops

07:00 - 08:00 (bicycle peak) 7 41 26

08:00 - 09:00 (vehicle peak) 16 32 33

12:30 - 13:30 (off peak) 4 15 14

17:00 - 18:00 (bicycle/vehicle peak) 2 19 29

ITACA

What is The ITACA system ?

� The Spanish fully adaptive system ITACA is very much a SCOOT look alike system

which was developed by Sianco Traffico with the assistance of an ex Plessey engineer.

ITACA has many of the characteristics of SCOOT but has been developed as one

might expect in a slightly different manner. Validation is referred to as calibration,

STOC values reflect discharge values, vehicles left at the end of green, max queue,

journey time and a percentage weighting until correlation exercise reflecting the

number of vehicles left at the end of green between street and the model output is

achieved.

� The placement of inductive loops or video detectors in ITACA follows the same

general rules as SCOOT i.e. typically 110 meters from the stop line and at the mouth

of the junction for the identification of turning vehicles. Link diagrams and Sub Areas

and Regions are also defined.

ITACA applications

RONDO

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� RONDO, that is ROlling-horizoN based Dynamic Optimization of signal control, is a

newly developed real-time traffic adaptive signal control system that aims to reduce

the response delay against the sudden changes of traffic flow. RONDO project started

in 1998. Since then we have added continuous enhancements to RONDO. Now,

RONDO is challenging the new problems, which are to promote traffic safety and to

protect the environments with keeping traffic efficiency. In this paper, we introduce

the latest additional functions to solve these problems. And we have a plan to install

the pilot system at the beginning of 2001. To prepare that, we have conducted two

traffic field surveys. We will also introduce the simulation experiment results using the

real field data.

� RONDO also has the other function, which is called “the dilemma zone actuated

control”. It detects the presence and the speed of the vehicle in the dilemma zone,

where vehicles cannot stop at the stop-line with safety deceleration and cannot go

through the intersection before the signal turns red. Then green signal is lengthened or

shortened according to the information.

Further Enhancements

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� Fig.1 shows the image of RONDO cycle length movements, when restriction is given.

The second is to use both RONDO and right-turn actuated control. It is so difficult to

predict the right-turn timings of vehicles in advance correctly that RONDO cannot

always control right-turn vehicles well. Therefore, RONDO entrusts right-turn

vehicles handling to right-turn actuated control that lengthens and shortens right arrow

phases according to the detection of the vehicles presence in right-exclusive lane.

Fig.1: Image of RONDO Cycle Length Movements

UTOPIA

TRAFFIC SIGNAL CONTROL SYSTEM – UTOPIA

GENERAL FEATURES

UTOPIA (Urban Traffic OPtimisation by Integrated Automation) is an adaptive traffic signal

control system which determines and actuates optimum management strategies for the

regulation of urban traffic. The system is able to operate on highly complex networks and

determine control strategies taking into account priorities assigned to public transport and

private traffic through the evaluation of historical data, real time traffic measurements and

predicted events. Its modular structure and the completeness of the system means that it is

simple to implement and ensures the possibility of later expansion. The aim of the system is

to improve traffic conditions over the whole urban area by minimizing trip times for private

traffic while giving priority to public transport vehicles. In creating a more fluid circulation

of vehicles, it leads to energy savings, a reduction of emissions and increase in safety. For a

transport authority responsible for traffic control and supervision, UTOPIA provides the

possibility of monitoring in real time the state of traffic across the whole road network and

identifying any interruptions in the flow. The system makes available various types of

statistics on mobility and traffic flows. It also provides timely information on any

malfunctioning of the signalling system, making it possible to intervene rapidly for

maintenance operations.

UTOPIA is able to interface with other systems, supplying detailed data on traffic conditions

(e.g. traveller information via Internet, Televideo, RDS/TMC, DAB) and permitting

management of priority requests (e.g. SAE-AVM systems). UTOPIA has a two-level

distributed architecture. The upper level consists of a central subsystem responsible for

medium and long term forecasting and control over the whole area concerned. At this level,

the traffic light reference plans and also the criteria needed for the adaptive co-ordination are

calculated dynamically. In addition, a continuous diagnostic activity is carried out for the

whole network. The lower level consists of a network of Multifunctional Units with the

function of Local Controllers (SPOT). These are interconnected, and each is responsible for

the management of one intersection. The Local Controllers determine in real time the

sequence and optimum length of traffic light phases, using the co-ordination criteria

established by the upper level, traffic measurements detected locally and information

received from the Controllers of adjacent intersections. Each SPOT carries out a permanent

diagnostic activity in relation to the system components, the peripherals and traffic sensors,

and communicates the situation to the upper level.

The main components of the system are: the Central Traffic Control System; Local

Controllers based on the multifunctional units (MFO) incorporating SPOT software; the

Communications Network, made up of connections between the multifunctional units and the

connections between the Central Control System and certain multifunctional units.

The System possesses the ability to:

ž What is the benefits of UTOPIA ?

ž identify and recognize "on line" the variations in traffic conditions;

ž give sufficient independence to each individual intersection to allow it to modify the

traffic light control strategy in relation to traffic conditions, and to co-ordinate with

adjacent intersections in function of the traffic dynamics;

ž provide the individual intersection with the capacity to exchange information required

for the calculation of co-ordinated and consistent variations in the plan;

ž ensure efficient self-diagnosis through centralized monitoring of the state of the

network;

ž continue to function even in the case of breakdown of a fundamental system

component;

ž ensure a high degree of modularity and immediate expansion to adjacent intersections;

ž considerable advantages in relation to the maintenance of the system through rapid

diagnostics and the ease of intervention to modify any signal plan setting.

THANK YOU