CSTR: Part D032 Design – Traffic Signals
Edition: February 2011
PART D032
DESIGN - TRAFFIC SIGNALS
CONTENTS
1.
2.
3.
4.
5.
6.
General
References
Traffic Signal Operational Performance
Design Requirements
Traffic Signal Hardware
Records
1.
GENERAL
This Part specifies the requirements for the design of traffic signals. The design of the conduit system shall comply
with Part D030 "Design – Conduit Systems".
"TMC" means the DPTI Metropolitan Region Traffic Management Centre located at Norwood.
“SCATS®” means the Sydney Coordinated Adaptive Traffic System, property of RTA NSW (refer
http://www.scats.com.au).
2.
REFERENCES
Unless specified otherwise, all design shall be undertaken in accordance with the following:
1) Road Traffic Act 1961 (South Australia).
2) DPTI: Code of Technical Requirements for the Legal Use of Traffic Control Devices.
3) DPTI: Road Design Standards and Guidelines, available from: http://www.dpti.sa.gov.au/standards.
4) DPTI: Operational Instruction 14.2 Traffic Signal Faces, available from:
http://www.dpti.sa.gov.au/standards/tass
5) AS 2144: Traffic Signal Lanterns.
6) AS 2578: Traffic Signal Controllers.
7) Austroads: Guide to Traffic Management.
8) AS 1742: Manual of Uniform Traffic Devices.
9) National Transport Commission Performance Based Standards Scheme Network Classification Guidelines
(“NTC Guidelines”).
3.
TRAFFIC SIGNAL OPERATIONAL PERFORMANCE
3.1
General
Traffic signal performance analysis shall include capacity analysis to guide the design and operational requirements
of traffic signals. Analysis will require modelling using current and future design flows, as specified and shall
include detailed assessment of the traffic impacts of alternative traffic management arrangements to be used during
construction of the project.
The following design and operational requirements shall be achieved:
(a) lane, phasing and coordination requirements at traffic signals that ensures the safe and efficient operation of
road network for the current and future design flows, as specified;
(b) traffic signals integration within the Principal’s current systems used to monitor and control traffic signal
operation; and
(c) the needs of all road users (e.g. buses, heavy vehicles, freight, cycles, pedestrians) are taken into account.
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The Contractor shall provide the following documentation:
(a) Traffic Signal Operation Performance Report, which will demonstrate that the requirements of the
Project Design Brief are met, including a report of any variations from these requirements; and
(b) Design Documents, suitable for describing the detailed requirements for the installation of the traffic
signals (refer Clause 5 “Design Documents”).
3.2
Operational Analysis
3.2.1
General
The traffic signals analysis shall include:
(a) base and proposed model(s) fully calibrated and validated to reflect the existing and projected traffic
conditions; and
(b) analysis of all major construction staging traffic signal arrangements, including a detailed assessment of the
performance of the proposed interim traffic signal operations.
This shall be fully documented in the Traffic Signal Operation Performance Report.
3.2.2
SIDRA Analysis
The Contractor shall undertake modelling to determine traffic flow performance using the latest version of aaSIDRA
for analysis of individual sites. The modelling shall comply with the requirements of the Project Design Brief. The
SIDRA analysis shall confirm that the proposed traffic signal design and operation will satisfy the performance
criteria specified in Table 3.2.2.
Table 3.2.2
New Signals
Temporary Signals
Degree of Saturation for each signal site
≤ 0.9
≤ 1.0
Level of Service (LOS)
"D" or better
"E" or better
The SIDRA analysis shall:
(a) use fixed time traffic signal control;
(b) model to the cycle length of the current maximum cycle length set in SCATS® or use the optimised cycle
length to a maximum value of 150 seconds;
(c) calibrate saturation flows in the base model to reflect those experienced in existing traffic conditions;
(d) for new intersections, use default values from SIDRA modified to reflect intersection geometry and traffic
composition;
(e) where analysis includes existing signal sites, use the current controller settings for red / yellow and
pedestrian times;
(f) for new traffic signal sites, design the time settings (e.g. red and yellow times, pedestrian times); and
(g) incorporate pedestrian movements in the phasing at sites where there is a demand identified.
3.2.3
Other Network Analysis
Where the proximity of traffic signals, major intersections, level crossings or other traffic controls may generate
queuing through traffic signal or level crossing sites such that operation cannot be effectively modelled using a
SIDRA, the Contractor shall use other network modelling tools to analyse the extended road network. The analysis,
in consideration of the queuing effects, shall confirm that performance criteria comply with those set out in
Clause 3.2.2 “SIDRA Analysis".
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The Contractor must choose appropriate modelling tool(s), preferably an application currently in use by the
Principal, which currently includes:
(a) AIMSUN;
(b) TRANSYT; and
(c) LINSIG
3.3
Other Design and Operational Requirements
3.3.1
Turn Movements
All turning paths shall cater for appropriate design vehicle type and size as specified in Part D021. Consideration
shall be given to these turning paths in designing the most effective phasing for the intersections and the implications
for the physical intersection arrangement to maximise the traffic throughput.
Right turn lanes and left turn lanes shall be designed with turn bays to remove through lane interaction and short
queue effects.
3.3.2
Heavy Vehicles and Buses
The design shall clearly show how the affect of heavy vehicles and buses on design flows and signal timings are
taken into account. In particular the design shall allow for the yellow and all red clearances for long vehicles
required by Section 2.5 “Signalised Intersections” of the NTC Guidelines.
3.3.3
Video Surveillance (CCTV cameras)
The design shall include video surveillance coverage at intersections and approaches at:
(a) All level crossing sites where queue management strategies are required to prevent queuing over the level
crossing;
(b) Any intersection or length of road where monitoring and changes to traffic signal operation is required on a
regular basis, such as:

New permanent traffic signals;

New signals under construction (or temporary signals) where intersection geometry and phasing
requirements will be subject to ongoing changes over an extended period of time (e.g. 6 months);

Reversible lanes / Variable lane use; and

Sites impacted by regular special events.
Where CCTV is required to be installed at intersections, the roadside equipment shall be housed in a “top hat” type
cabinet attached to the top of the traffic signal controller cabinet.
3.3.4
Traffic Signal Coordination
The Contractor shall demonstrate, by use of traffic modelling techniques, that the traffic signals will be capable of
being effectively coordinated with adjacent traffic signal controlled sites, including traffic signals located outside of
the Site.
3.3.5
SCATS Communication
All traffic signal controllers shall be connected to SCATS.
3.4
Traffic Signal Operation Performance Report
The Contractor shall produce a report describing all aspects of traffic signal operational performance and provide a
copy at the following stages:
(a) the project planning phase (where appropriate);
(b) at the notional 15% design stage; and
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(c) at the notional 95% design stage
The Superintendent will forward the report to the DPTI Senior Network Management Engineer (Metropolitan
Region).
The report shall include a report on intersection performance, which shall list outcomes using specified design traffic
flows and shall include:
(a) Intersection layout plan;
(b) Traffic signal phasing;
(c) Offset parameters for linking to adjacent traffic signal sites;
(d) Degree of saturation, LOS and 95th percentile queue lengths for individual movements;
(e) Discussion of alternative schemes considered; and
(f) Any variations from the requirements in this part.
4.
DESIGN REQUIREMENTS
The design shall comply with the following:
(a) the operational performance requirements documented in the Traffic Signal Operation Performance Report;
(b) all turn movements shall be designed to cater for the maximum vehicle size for geometric design as
specified in Part D021;
(c) signal groups, detectors, phasing and pole shall be designed (and where appropriate, numbered) in
accordance with DPTI standard drawings TC 202 and TC 203 “Traffic Signal Design Guide”;
(d) design of pedestrian activated crossings shall be in accordance with DPTI standard drawings:
 GD 704 “PAC Standard - No Median”,
 GD 705 “PAC Standard Dual Carriage Way Raised Median more than 3m”, and
 GD 706 “PAC Standard Dual Carriage Way Raised Median more than 3m”;
(e) the design of the turn movements shall be checked to ensure that adequate provision has been made to cater
for all possible traffic signal phase arrangements and sequences;
(f) pedestrian displays shall be incorporated in the phasing at sites where there is a demand identified by the
design process;
(g) provision of vehicle and pedestrian detection shall be included at all signalised intersections;
(h) a vehicle stopline detector is required for every discrete traffic lane at an intersection including left turn
lanes which may not be controlled by a signal group; and
(i) the design shall be documented in accordance with the drafting standards shown in DPTI standard drawing
DP 115 “Traffic Signal Layout”.
The standard drawings listed above are available from:
http://www.dpti.sa.gov.au/standards/road_design_standards_and_guidelines
5.
DESIGN DOCUMENTS
At a minimum, the Design Documents shall include the following:
(a) drawings and schedules:

traffic signal layout drawings;

signal duct layout drawings;

site wiring diagrams;

cable connection schedules;

hardware schedules;

traffic signal phasing plan; and
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CSTR: Part D032 Design – Traffic Signals
equipment drawings;
(b) details of the following:

system description;

reference to all applicable standards and specifications;

details of design inputs from the Traffic Signal Operation Performance Report;

details of Interfaces to existing or third party systems;

operational description, including phasing philosophy;

location of all equipment;

explanations for non-standard equipment locations;

controller input/output allocations;

signal group allocations;

detector input allocations;

power system, volt drop and fault loop impedance calculations;

details of all proposed construction materials;

construction designs for all equipment; and

design, procurement, installation integration and commissioning program.
6.
TRAFFIC SIGNAL HARDWARE
6.1
Location of Signal Equipment and Signal Face Layouts and Display Sequences
The arrangement of traffic signal faces shall be in accordance with DPTI: Operational Instruction 14.2 “Traffic
Signal Faces”.
6.2
Traffic Signal Lanterns
At new traffic signal sites, all traffic signal lanterns shall use a Light Emitting Diode (LED) optical system, comply
with AS 2144 and be approved by the Principal. A list of approved products is included in Appendix 1. Details of
the Contractors proposals in regard to these products are to be included in the Traffic Signal Operation Performance
Report at the 15% design stage;
Where additional lanterns are to be provided at an existing signal site, all the lanterns shall be changed to LED.
200mm or 300mm aspects shall be provided in accordance with DPTI: Operational Instruction 14.2 “Traffic Signal
Faces”.
6.3
Traffic Signal Controller
All new traffic signal controllers shall conform to RTA NSW specification TSC/4 and be approved by the Principal.
A list of approved products is included in Appendix 1. Details of the Contractors proposals in regard to these
products are to be included in the Traffic Signal Operation Performance Report at the 15% design stage.
The traffic controller specified shall be vehicle actuated and vehicle actuation shall be provided to enable SCATS®
operation.
The location of the traffic signal controller shall be determined using the following criteria:
(a) minimisation of obstruction to pedestrians;
(b) minimisation of visual obstruction to drivers;
(c) minimisation of the risk of accidental damage by traffic;
(d) provision of a safe and easy access for maintenance personnel and associated vehicles;
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(e) permits maintenance staff to have a clear view of the whole of the intersection from the controller;
(f) orientation so that the cabinet doors to open away from the centre of the intersection; and
(g) close location to the power supply and telecommunications service.
6.4
Programming of Traffic Signal Controller(s)
The Contractor shall be responsible for supplying the personality for the controller, including the personality
module. The personality module contains the personality for the controller(s).
DPTI Metropolitan Region will provide the Contractor with a personality programming service at no cost, subject to
the following conditions:
(a) the Design Documents (including all reports and drawings) are complete and the Contractor has been
released from the Hold Point on the Final Design and Construction Report; and
(b) not less than 8 weeks prior to the required delivery date of the program personality , the Contractor has
requested (in writing) the DPTI Metropolitan Region to provide programming of the controller and also
provided all Documentary information necessary for the programming.
6.5
Approval of Traffic Control Devices (Traffic Signals)
Traffic signals are traffic control devices requiring approval under the Road Traffic Act. The Contractor shall be
responsible for ensuring that the traffic signals are properly approved. DPTI Metropolitan Region can arrange for
the completion of this approval process subject to the supply of accurate plans 8 weeks prior to switching on new
traffic signals, or changing the personality(s) in existing traffic signals.
6.6
Provision of Telecommunications for SCATS®
6.6.1
New traffic signal sites
The traffic signal controller(s) shall be connected into SCATS® by means of a modem and Telstra ‘dial-ip’ data
service into an existing SCATS® communication network. The Contractor shall be responsible all costs associated
with the communications connections and for the provision and connection of the modem and Telstra ‘dial-ip’ data
service, which includes:
(a) Microconnect PSTN Linking Control Module (LCM) PSTN modem
(b) Telstra ip-WAN access
(c) Traffic Site specific parameters
6.6.2
Linking Control Module
The Contractor shall be responsible for the procurement, installation and programming of the Linking Control
Module (LCM). The LCM must be an approved product (refer Appendix 1).
6.6.3
Telstra ip-WAN Access.
The Telstra ip-WAN access consists of a PSTN telephone service. The Contractor shall apply to Telstra for a PSTN
telephone on behalf of the Principal. The Contractor shall quote the following product codes when making the
Telstra PSTN application:
(a) - Easy call barring (product code: ECCWNO)
(b) - Contract pricing (product code: TLI100)
6.6.4.
Traffic Site specific parameters
The Contractor shall liaise with a DPTI TMC representative to determine:
(a) ip-WAN username and password
(b) traffic site ip-address
(c) LCM Smartcard configuration parameters.
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6.6.5
CSTR: Part D032 Design – Traffic Signals
Documentation
The Contractor shall document the following information in relation to the traffic signals in the Design Documents:
(a) traffic site number
(b) SCATS® “slot” number
(c) Telstra PSTN and port service numbers
(d) Confirmation of site specific parameters.
Upon written request, DPTI Metropolitan Region (on behalf of the Principal) will supply the necessary information
to permit the Contractor to arrange the purchase of these services. The Principal does not warrant the time of
delivery of this information and the Contractor shall allow at least 2 weeks from the request to delivery.
6.7
Vehicle Detection
Where inductive loops are utilised for vehicle detection, the loops shall be as detailed on DPTI Drawing No. S-4500
sheets 1 and 2: Detector Loop Layouts. Detector loops located at the intersection stop bar shall be the quadrupole
type, while other traffic signal loops shall be the passage type.
Vehicle stop line type detectors suitable for SCATS® operations shall be provided for all lanes irrespective of the
control function. Loops on non-controlled lanes e.g. left turn lanes, shall be provided and connected to traffic
controllers and shall be used for counting.
Advanced detectors shall be considered on approaches with speed limits 80 km/h and over. Locations to be
calculated on the basis of the design speeds and shall consider the approach gradient. Alternatives to loop detection
will be considered providing they are compatible with SCATS® operation.
6.8
Pedestrian and Bicycle Detection
All pedestrian movements shall be demand actuated by audio tactile pedestrian push buttons. Pedestrian push buttons
shall:
(a) be installed at 1 m height above the standing place used by pedestrians when operating the button.
Pedestrian;
(b) be orientated so that the face of the push button is in line with or parallel to the crosswalk marking;
(c) incorporate arrow legends (in the audio tactile display) on all pedestrian push buttons;
(d) be correctly oriented to guide visually impaired pedestrians in the same direction indicated by cross walk
markings;
(e) be provided on median traffic islands; and
(f) incorporate microwave pedestrian sensors where pedestrian displays are controlling marked foot crossings
15 m and longer.
Cycle push buttons shall be provided on side road approaches. Cycle Push button faces are to be parallel to the kerb.
In-ground loop detection in cycle lanes shall be provided where these are provided between marked vehicle lanes
6.9
Level Crossings
Interlocking between adjacent level crossings and traffic signal installations shall be provided by the provision of a
hard-wired connection.
Level crossings are considered adjacent with traffic signals where the traffic signals could be interpreted to conflict
with the level crossing wigwag signs or where the level crossing is expected to create queues across the intersection,
or visa versa. There shall be a cable link provided in duct between the level crossing controller and the traffic
controller, which will enable the traffic signal controller to be forced to a "safe" state before the level crossing closes
to permit the passage of a train.
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6.10
Traffic Signal Posts
The location of traffic signal posts shall take into account site constraints such as services and roadside furniture.
The post location(s) shall ensure that the signals can be sighted where they can be clearly seen by approaching
drivers.
Under no circumstances shall traffic signal posts be located within painted medians/islands; i.e. where there are no
kerbed islands or an area physically raised from the road, which is designed to discourage overrunning by vehicles.
Wherever possible, combination poles comprising street lighting and or mast arms shall be provided to minimise the
number of signal posts.
6.11
Pavement Markings
Where the speed limit is 80 km/h or higher, 600 mm stop lines on approaches shall be provided.
6. 12
Signs
Where regulatory signs are to be provided for part time regulation, a symbolic internally illuminated sign (no left
turn/no right turn) shall be provided at a stop line pole and a secondary (or tertiary) pole.
7.
RECORDS
The following records shall be provided to the Superintendent:
Drawings
The drawings described in Clause 5 “Design Documents” and the DPTI: Road Design Standards and
Guidelines.
As constructed drawings.
Reports
Traffic Signal Operational Performance Report.
The details described in Clause 5 “Design Documents”.
The details described in Clause 6.6.5 “Documentation”.
Implementation Records
Approval of Traffic Control Devices (refer Clause 6.5).
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APPENDIX 1
PRODUCTS CURRENTLY APPROVED FOR USE BY THE PRINCIPAL
TRAFFIC SIGNAL CONTROLLERS
PRODUCT
SUPPLIER
Aldridge ATSC/4
Aldridge Traffic Controllers
Tyco eclipse
Tyco controllers
TRAFFIC SIGNAL LANTERNS
PRODUCT
SUPPLIER
Aldridge LED
Aldridge Traffic Systems
GE/GelCore LED*
Saferoads
* Currently awaiting final approvals
LINKING CONTROL MODULE
PRODUCT
SUPPLIER
Microconnect LCM
Microconnect
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