Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020)

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39. Mean time between failures (MTBF) of the installed controller shall be greater than 100,000

hours.

40. Volume - density operations: Microprocessor controllers shall provide for volume- density

operation. In this mode of operation, the green interval in each phase shall consist of a
minimum green and a vehicle extension.

41. Minimum green time shall be guaranteed irrespective of whether vehicle demand exists or

not.

42. Vehicle actuation: Full vehicle actuation shall be provided as specified herein. However,

signals shall also be capable of operating in a semi-actuated mode with a selected phase
given priority whereby signals shall rest in that phase until vehicular demand is recorded for
another phase. It shall be possible to place any or all phases on recall at the local controller
without the use of special tools. Signals shall also be capable of operating in a pre-timed
mode with phasing and sequencing shown on the Contract plans.

43. Vehicle extension (passage). The vehicle extension (passage) shall be reset by vehicle

actuations on this phase when the signal is green (after minimum green has expired) and
shall commence timing when the actuation is removed.  This period shall change by reducing
the  allowed  gap  between  successive  vehicle  actuations  from  the  maximum  gap  to  the
minimum  gap  parameters  which  shall  also  be  capable  of  being  loaded  into  the  controller
through the front panel.  Gap reduction increment and frequency shall be as prescribed by
the parameters Reduce Gap By and Reduce Gap Every which shall also be capable of being
loaded into the controller through the front panel.  Gap reduction shall begin with arrival of
the first vehicle actuation on an opposing phase after minimum green has expired.  Upon
expiration  of  the  allowed  gap  (gap  timer)  the  green  interval  shall  be  terminated.    Vehicle
extension portion of the green shall also be terminated if the maximum extension has been
exceeded.    Amount  of  the  maximum  extension  shall  be  capable  of  being  loaded  into  the
controller through the front panel.

44. Pedestrian signal control: Pedestrian signals shall be controlled by the local intersection

controllers.    Pedestrian  signal  intervals  shall  be  capable  of  being  timed  concurrently  with
vehicular  phases  as  well  as  being  timed  as  independent  phases.    Appropriate  pedestrian
Red Clearance shall coincide with the later part of vehicular Green indication and vehicular
Amber  indication.  Pedestrian  actuation  of  signals  will  be  required.    Capability  for  full
pedestrian actuation shall be provided in each controller.

45. Pedestrian intervals and termination of green: Pedestrian timing shall be concurrent with the

above  vehicle  intervals  (Minimum  green time  and  Vehicle  extension).  Pedestrian  intervals
shall consist of a walk indication, a flashing walk indication, and a solid don't walk indication.
Vehicle  green  interval  shall  normally  terminate  if  the  minimum  green  has  expired,  the
pedestrian cycle has completed, an opposing call is present and one of the following events
has occurred:

Extension time has expired

ii.

Gap timer has expired

iii.

Maximum extension has expired

46. Clearance intervals: Following the green interval, there shall be a flashing green and yellow

(amber) change interval which is timed in accordance with the setting for that phase. There
shall be provision for an all red interval following the yellow interval.

47. Ranges and increments: Ranges and increments of the volume-density timing intervals for

each phase shall be as shown in Table 9-8.

Table 9-8 : Ranges and increments

Interval

Range (sec)

Increment (sec)

Minimum green

0 - 199

Extension (passage)

0 - 19.9

0.1

Maximum extension

0 - 199

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Interval

Range (sec)

Increment (sec)

Added per actuation

0 - 19.9

0.1

Maximum gap

0 - 19.9

0.1

Minimum gap

0 - 19.9

Reduce gap every

0 - 19.9

0.1

Reduce gap by

0 - 19.9

0.1

48. Signal indication ranges and steps: Signal indications shall have controls for each phase as

shown in Table 9-7

Table 9-9 : Ranges and steps

Vehicular green

Range (sec)

Increment (sec)

Minimum green

0 - 199

Extension

– 19.9

0.1

Maximum

– 199

Vehicular amber clearance

– 19.9

0.1

Vehicular red clearance (all

red)

– 19.9

0.1

Pedestrian green (walk)

– 199

Pedestrian clearance (flashing

walk)

– 199

49. Manual control: Manual controls shall be provided to permit vehicular and pedestrian signals

to switch to any related phase, or to display red indication in all directions, or to switch from
one time plan to another.

50. Stand-alone operation: Stand-alone operation shall consist of two modes as follows:

Free running mode: In this mode the controller shall not be coordinated and shall
operate as a fully-actuated controller.

ii.

Time-base Coordination Mode. In this mode signals shall operate on a stand-alone
basis in accordance with a minimum of seven different timing Drawings.

iii.

Change from one mode to the other and among different timing plans in Mode (b)
shall be automatic and pre-programmable on a time-of-day and day-of-week basis.
However, capability to switch manually from one mode to the other or from one timing
plan to another shall also be provided.

51. Coordination operation: Controller shall be capable of following the commands of the artery

master controller and/or the existing central computer control.  In this mode, each controller's
timing parameters shall be as dictated by the artery master controller or the central computer
control.    All  clearance  intervals  shall  be  preset  at  the  local  controller.    The  duration  of
clearance  intervals  shall  not  be  overridden  by  the  artery  master  controller  or  the  central
computer control.

52. Flashing mode: Signal shall have the capability of operating in a flashing mode whereby

vehicular signals controlling the main road shall show flashing yellow and vehicular signals
controlling the turning movements and cross roads shall show flashing red indication, and

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pedestrian signals  in  all directions  shall  be  turned  off.    Capability shall  be  provided  for  an
alternative  flash  mode  whereby  vehicular  signals  controlling  the  main  road  shall  show  no
indication,  vehicular  signals controlling the turning movements and cross roads shall flash
showing amber indication, and all pedestrian signals shall be turned off.

53. Voice communications: Audio communications equipment shall be included in each

controller cabinet to provide voice communications between the intersection controller, the
artery master controller, and the central computer system.

Subcontractor shall bring electric power to the automatic transfer dual power supply panels and on
to the local controllers in accordance with the authority requirements. A fuse shall be provided to
protect the controller circuitry against surges in the electric power.

b. Controller Cabinets

All local control equipment at a given intersection shall be mounted in a single waterproof cabinet
made of fibre-glass reinforced polyester housing or similar approved materials. All cabinets shall be
sized to yield 20 % unused shelf space when all equipment necessary for proper operation including
communication equipment is installed and operating.

Cabinet shall provide a door, complete with all hardware, of sufficient size to permit easy access for
maintenance of the enclosed equipment.  Hardware shall include but not by way of limitation a latch
type handle, mortise lock (master-keyed), stainless steel or other durable hinges and appurtenant
materials.   Inside  of the controller  door shall  be equipped  with  a  built-in documentation  pocket to
house a complete set of operating and maintenance documents.  It shall be possible to operate the
controller in a manual mode without opening the large door (e.g., via a "police panel" or a remote
panel attached to the cabinet).

All equipment necessary to properly mount the cabinets (including mounting poles if required) and
to install the local control equipment in the cabinet shall be provided by the Contractor.

Lightning arrester (thyrector) shall be installed in each cabinet adjacent to the terminal strip used for
grounding. Arrester shall be installed between the live wire and the ground on the supply side of the
circuit breaker or fuse. Live wire shall be connected directly to the lightning arrester. Connection
between the arrester and the grounding terminal strip shall be made by a number 8 AWG insulated
copper wire and shall be as straight and short as possible. Lightning arrester shall be of the self-
restoring type and shall be designed to operate when a potential from the live wire to ground exceeds
300 volts.

An electric power outlet shall be provided in each controller cabinet. Adequate screening facilities
shall be provided to protect all sensitive devices in the controller, so as to be immune to the electrical
noise and spikes generated by the switching operation and/or induced on the power side from any
source whatsoever.

Each  cabinet  shall  be  provided  with  a  fan  rated at  a  minimum  of  2.8  m3  per  minute.    The  fan  or
cooling system shall be capable of operating continuously for a minimum of 6,000 hours in a 50o C
environment,  without  the  need for  after-installation  maintenance.    Each  cabinet  shall  be  provided
with a thermostat to control the operation of the fan or cooling system.   Thermostat turn-on point
shall be manually adjustable from 33° C and 45° C, with a differential of not more than 6° C between
automatic turn-on and turn-off.

Cabinets  shall  be  factory  wired  to  include  all  equipment  harnesses  and terminal  facilities for field
wiring  including  computer  communication  cables,  arterial  communication  cables,  audio
communication  cables,  traffic  violation  recording  equipment  cables,  lead-in  loop  wires  from  all
system and local detectors and signaling cables.  All terminals shall be labelled and leads wired to
the terminal strips shall be identified with marked aluminium or plastic sleeves.  Cabinet shall include
a  radio  interference  suppressor  which  shall  meet  Underwriters  Laboratories  Inc.  standards.
Minimum attenuation shall be 50 decibels over a frequency range of 200 kilohertz to 75 Megahertz
when used in connection with normal installations.

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Interference suppressor shall be hermetically sealed in a substantial metal case filled with a suitable
insulating compound. Terminals shall be nickel-plated with brass studs of sufficient external length
to provide for a suitable connection.

c. Solid State Load Switches

Signal light circuits shall be controlled by solid state load switches. Each circuit shall have a minimum
rating of 600 watts for tungsten lamp or gas tubing transformer load at 240 volts, AC.

Solid state load switches shall be functionally unaffected by transient voltages.  Fail-safe operation
for all signal lamp circuits shall be provided. The external load switches shall be wired so that all
opposing and conflicting traffic movements shall have red indication prior to the display of the green
indication on the phase which is to receive the right-of-way.  Each load switch shall be mounted in
the controller cabinet on a plug-in base by means of a plug-in mounting and shall be designed for
continuous duty.  Outputs of the load switches shall provide a Red, an Amber, and a Green indication
for the vehicle and overlap use; and a WALK and a DON'T WALK for pedestrian use. Flashing Red
and flashing Amber indications for vehicles, and flashing WALK indications for pedestrians shall also
be provided as specified herein.

d. Security Unit (Conflict Monitor)

A security unit (conflict monitor) shall be provided which shall monitor the output of the Green, Amber,
Red and Walk load switches. In the event a conflict condition exists, the security unit shall cause
the intersection to go to the emergency flash condition by performing the following functions:

1. Energize the external flash unit.
2. Disconnect or otherwise interrupt any coordination commands, whether they are from an

Artery Master or from the central computer.

3. Disconnect the local controller output from the load switches.
4. Hold and display the conflict conditions until reset.

Designation of conflicting phases shall be programmable without the use of special tools.

Intersection shall also go to the emergency flash condition under any of the following occurrences:

1.  Absence of required Red or Amber signal
2.  Absence of security program.
3.  Signals "hanging" indefinitely in one state (except the semi-actuation mode when there is no

vehicular demand in the cross road).

4. Processor fault condition.

e. External Flash Units

Each local controller cabinet shall contain a solid state flasher unit to drive the signal lights during
periods of controller maintenance or controller malfunction. When operating, the flasher shall flash
the red and amber indications in designated directions at a rate of 60 flashes per minute. Ratio of
the illuminated period to the dark period shall be as much as 60-40 but not less than 50-50.

It shall be possible to remove control of the signal lights from the local controller and give control of
the flasher unit in the following manner:

1.  Manually changing position of a single switch.
2.  Through automatic programming.
3.  Action of a conflict monitor.
4.  Action of a watchdog timer, as applicable.
5.  By command from the central computer.

All switches, solid state components and other ancillary equipment required to provide the operation
just described shall be provided and installed by the Subcontractor.

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f. Watchdog Timer

A  watchdog  timer  shall  be  provided  and  installed,  and  shall  be  used  with  microprocessor  based
controllers.  Purpose of this timer is to prohibit faulty controller operation from causing the signal light
indication  to  "hang"  indefinitely  in  one  state  (except  the  semi-actuation  mode  when  there  is  no
vehicular demand in the cross road).

When used, the controller shall reset the timer periodically. If allowed to time out, the watchdog
timer shall cause the signal lights to be put in the flash mode by performing, or causing to be
performed, the following actions.

1. Energize the external flash unit
2. Disconnect or otherwise interrupt any coordination commands, whether they are from the

Artery Master Controller or a Central Computer Control.

3. Disconnect the local controller output from the load switches.
4. Hold and display the conditions until reset.

Watchdog timer may be either part of the hardware of the local controller or an external device. All
switches, solid state components and other ancillary equipment necessary to provide the operation
just described shall be provided and installed by the Subcontractor.

g. Communications Interface

It  shall  be  possible  to  interface  all  controllers  with  an  artery  master  controller  and  the  central
computer control system.  All equipment necessary to interface a controller with the  artery master
controller  and  the  existing  central  computer  control  shall  be  provided  and  installed  as  part  of this
Project.

All local controller interface equipment required for the interface with artery master controllers and
the central computer control system shall be mounted in the local controller cabinet.

h. Communication Standards

System shall support internationally accepted standards for data transmission between the system
components at the central level, between the central level and the intersection level as well between
the units operating at the intersection level.

i. Communications Modules Rack

Communications modules rack shall be compatible with, and shall house, all fibre optic transceivers
and  components  at  the  TSS.  Transceivers  shall  comply  with  the  traffic  signal  control  system
manufacturer  requirement  as  specified  herein.  Transceivers  are  furnished  separately  from  the
communications  modules  rack.  Rack  transceivers  shall  communicate  with  the  local  controller
transceivers.  Rack  dimensions  and  configuration  shall  be  compatible  with  requirements  of  the
transceivers manufacture’s recommendations, as approved by the Engineer.

9.5.2.13

Artery Master Controller

If shown on the Contract plans or required in the Particular Specifications, an artery master controller
shall be installed by the Subcontractor. Artery master control equipment shall perform all functions
necessary to provide interconnection among individual intersections along a designated artery.

Artery master control equipment shall include but not by way of limitation the following major
components:

1.  Master controller
2.  Master controller cabinet
3.  Interconnection (system) detectors
4.  Communications interface equipment

Descriptions for each of the above-mentioned components are provided herein. The Subcontractor
shall provide any additional equipment necessary to make the system perform in accordance with

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the requirements of these Specifications, with good traffic engineering practices, in full compatibility
with any existing traffic control system, and to the approval of the Engineer.

a. Master Controller

Master controller shall be a microprocessor based device. Master controller shall be capable of
coordinating up to 10 fully-actuated local intersection controllers. Master controller timing shall be
digital in nature and based on a 50 hertz supply frequency.

Master controller design shall be fully compatible with the design of local intersection controllers and
shall include all necessary features to operate the local intersection controllers  in the progressive
mode as well as the independent (free) mode.  Interconnection of local intersection controllers to a
master  controller  for  progressive  traffic  flow  shall  not  negate  the  full  actuation  feature  of  local
intersection controllers.

It  shall  be  possible  to  change  master  controller  timing  parameters  manually  from  the  front  of  the
master  controller  cabinet  or  remotely  from  the  central  computer.    Those  changes  shall  be  made
either  by  inputs  via  the  front  panel  of  the  master  controller  or  through  use  of  a  portable  readout
device.  In the event a portable readout device is used it shall be connected to the master controller
via a plug-in on the front panel.  In the event the portable readout device is used, a minimum of two
shall be provided.

Master controller shall provide the following features:

1. In the event that more than one model of local intersection controller exists in a designated

artery, the master controller shall be capable of coordinating any such combination of local
controller models.

2. Master controller shall be capable of providing a minimum of eight pre-programmable

coordination time plans to accommodate changing traffic conditions.

3. Master controller shall be capable of coordinating local intersection controllers based upon

automatically obtained volume-occupancy data. Below a pre-selected level of volume and
occupancy, the master controller shall switch to independent (free) operation mode.

4. Master controller shall be capable of providing a minimum of three background cycle lengths

with each cycle length adjustable between 45 to 240 seconds at 5 second steps.

5. Master controller shall be capable of providing a minimum of three offsets per cycle. Each

offset shall be adjustable from 0 to 99 percent of cycle length in steps of one second.

6. Master controller shall have a built-in fail-safe system to assure proper functioning of local

controllers in cases of interruption in the communication system or any other system failure.

7. Audio communications equipment shall be included in the master controller cabinet to provide

voice communications between the master controller, the computer control centre and
intersection controllers.

Subcontractor shall, as part of this Contract, bring electric power to the artery master controller in
accordance with the authority requirements. A fuse shall be provided to protect the master controller
circuitry against surges in the electric power.

b. Master Controller Cabinet

All master controller equipment shall be mounted in a single waterproof, dust resistant, and climate
resistant cabinet made of approved materials. Cabinets shall be sized to yield 20 % unused shelf
space when all equipment necessary for proper operation is installed and operating. Equipment
required to interface with the central computer control system shall be considered as necessary for
proper operation (i.e., the central computer control interface equipment shall not require any of the
20 % spare shelf space).

An electric power outlet shall be provided in the master controller cabinet.

All materials, fixtures and appurtenances of the master controller cabinet shall be similar to that of
the local controller cabinets as described in Sub-article b of Article 9.5.2.12.

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c. Interconnection (System) Detectors

If  the  artery  master  control  system  to  be  installed  under  this  Contract  requires  interconnection
(system)  detectors  at  locations  other  than those  shown  on  the  Contract  plans,  the  Subcontractor
shall provide and install the necessary detector amplifiers, loops, lead-in wires and conduit.  Such
equipment shall conform to the  Specifications  and requirements set forth in  Article 9.5.2.11.  Any
other ancillary equipment required for the artery master control system to operate according to the
object of this Specification and to good traffic engineering practices shall be provided and installed
by the Subcontractor.

d. Communications Interface

All equipment necessary to interface a master controller with the central computer control shall be
provided and installed as part of this Contract.

Interface should be capable of transmitting and receiving all necessary data in a format which is fully
compatible with the existing central computer control system.

All master controller interface equipment required for the interface with the central computer control
system shall be mounted in the master controller cabinet.

9.5.2.14

Communications, and Intersections Placed under Central
Computer Control

Subcontractor shall provide all necessary communications means and equipment required for the
proper and satisfactory operation of the traffic control system and its parts and components.
Communications equipment and protocol shall be IP based and fully compatible with the existing
traffic control computer system.

Communication  system  shall  connect  specified  arterial  master  controllers  and  specified  local
intersection traffic signal controllers to the central traffic control computer.  Information carried by the
communications system shall consist of commands issued to local controllers by the central control
computer.  In addition, the communications system  shall carry local traffic signal controller  status
information and traffic flow information from system detectors through each signal controller to the
central computer.

Commands from the central computer to each local controller shall accomplish the following
functions:

1.  Place controller under computer control
2.  Release controller from computer control and place controller in free running mode.
3.  Release  controller  from  computer  control  and  place  controller  in  time  based  coordination

mode.

4.  Release controller from computer control and place controller under arterial master control.
5.  Stop and start controller timing.
6.  Step controller to next phase.
7.  Issue yield command to local controller.
8.  Issue force-off phase command to local controller.
9.  Alter phase sequence of local controller.
10. Alter timing interval durations.
11. Synchronize controller clock.
12. Respond to request to return controller status and surveillance data.

Data to be carried by the communications system emanating from each local controller shall provide
for displaying the following information at the central control room:

1. Current controller phase
2. Traffic flow surveillance data sensed by the system detectors and consisting of volume,

speed, occupancy, stops and delay.

3. Indication that vehicle violation recorder sensed a vehicle crossing the violation detector

during the red interval.

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4. Any messages regarding malfunctioning of controller.

Communications system protocol including polling rate, polling sequence, data message format, and
bit transmission rate shall guarantee that traffic signal timing plans generated and/or implemented
by the central computer shall have a maximum granularity of one second. That is, phase durations,
interval durations, cycle lengths, and offsets shall be designated and commanded in increments of
one second.

Local intersection traffic signal controllers shall be programmed such that any command issued from
the communications system which is unrecognizable will be ignored.  If successive commands are
received which are unrecognizable, or if no commands are received over a prescribed duration of
time, the controller shall automatically release itself from control of the computer and subsequently
operate  in  the  standalone,  Time  based  coordination  mode.    Controller  should  be  capable  as  a
standalone  controller,  to  store  a  time  schedule  to  switch  between  stored  signal  time  plans  for  a
schedule of up to 7 days.

Local intersection traffic signal controllers shall also be programmed such that force-off commands
issued from the communications system shall be ignored by the controller if the minimum green has
not expired or if the controller is in a clearance sequence.

All  clearance  intervals  shall  be  timed  and  commanded  by  the  local  intersection  controller  in
accordance  with  the  clearance  interval  times  (inter-green  times)  contained  in  memory  of  the
controller.  It shall not be possible to override the local controller clearance times through information
received from the communications system.

Central traffic control computer shall be programmed such that the receipt of erroneous controller
status data, or the non receipt of data, from the data communications system for a prescribed period
of time shall cause the Central Control Computer to automatically cease attempting to command the
local intersection controller. Operator intervention shall be required to reattempt commanding the
local controller under these circumstances.

Placing a full-actuated, or semi-actuated, local intersection controller under central computer control
shall not disallow the actuation capability of the local controller.  A cycle length shall be maintained
through controlling the duration of time between issuances of successive yield commands.  Phase
durations  at  the  local  controller  shall  be  governed  by  local  vehicle  actuations  except  when  the
maximum phase times allocated by the central traffic control computer are reached.  Under these
circumstances  the  central  computer  shall  issue  a  force-off  command  to  the  local  controller  to  be
transmitted over the data communications system to advance the controller to the next phase.

Communication equipment installed shall provide prompt, accurate, effective, and fail-safe
communications among signals, local controllers, master controllers, central computer control
system components, and shall include cable, communications interface equipment and other such
elements as shown on Contract plans, the Subcontractor's shop drawings, as specified herein and
as approved by the Engineer for satisfactory operation of the traffic control system.

All pullboxes, junction boxes, and conduits shown on the Contract plans shall be supplied and
installed by the Contractor if included in the Particular Specifications and the Bills of Quantities.

Due to limited space in the utility service reservations, no more than four, 100 mm diameter, concrete
encased PVC conduits will be available for the computer to controller communications link on any
given conduit run. All communications must be accomplished using cables.

Wireless radio signal communications are subject to the regulating authority approvals. .

Voice  communications  from  intersection  to  intersection,  from  intersections  to  artery  master
controllers,  and  from  intersections  and  artery  master  controllers  to  the  central  computer  control
system shall be provided as an integral part of the communications system.  Wireless radio signal
communications are subject to the regulating authority approvals.

All communications cable used in this Contract shall be installed underground and protected by
conduit. No overhead cable or underground cable without conduit will be allowed.

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Requirements  and  constraints  of  the  data  communications  system  described  in  this  Specification
shall  be  accommodated  using  conventional-type  insulated  electric  cable  as  described  in  Article
9.5.2.5  and  by  employing  a  multiplexing  communications  system  which  is  compatible  with  the
existing system.

a. Intersection Placed under Central Computer Control

When specified that an intersection shall be placed under central computer control, it means that all
necessary  communications  interface  equipment  shall  be  provided  and  installed  such  that  to/from
data communication between the local traffic controller at the intersection and the central computer
shall take place.  Data communication shall be in a format which is fully compatible with the existing
central computer control system  and which consists of commands from the  central computer  and
data from the local controller  as described in  Article 9.5.2.14.  It includes all necessary hardware
additions to the central computer control equipment, all cable and wiring (except communications
and  audio  transmission  cables  between  the  central  computer  and  the  local  intersection  signal
controller),  interfacing  with  and  updating  of  the  wall  map  display  in  the  computer  centre,  and
interfacing with all necessary central computer components and peripherals.

It  also  includes  software  programming  to  integrate  the  intersection  operations  with  the  traffic
engineering software and the existing area control and group control programs, and development
and implementation of necessary traffic signal plans in the central computer control system.  All of
the  above  shall  be  performed  such  that  full  compatibility  and  integration  with  the  existing  central
computer control system is ensured and it is to the approval of the Engineer.

9.5.2.15

Automatic Transfer Dual Power Supply Panels

Automatic transfer power supply panels shall be of the plinth mounted free standing type equipped
to  provide  power  supply  for  the  traffic  signalling  related  equipment  at  an  intersection.    Automatic
transfer power supply panels shall be fed from two different substations to enhance the availability
of  the power supply system  and shall be equipped to connect a standby genset automatically on
power  failure  as  detailed  below.    Panel  shall  be  equipped,  but  not  by  way  of  limitation,  with  the
following:

a. Main incoming feeders: There shall be two numbers of main incoming feeders each

equipped with a 40 A moulded case circuit breaker, a 45 A contactor, a voltage sensing relay,
a set of interlocking control and time delay relays, a healthy feeder indication light, a feeder
`on' indication light, and an on/off switch for manual operation.

b. Power Backup and Generator feeder: There shall be a generator feeder equipped with a 40

A moulded case circuit breaker, a 45 A contactor, a voltage sensing relay, a frequency
sensing relay, a generator running indicator light, a feeder `on' indicator light, an on/off feeder
control switch for manual control, a generator shutdown time delay relay, a set of auxiliary
interlocking and time delay relays, and a weather proof 5 pole socket outlet installed in the
side wall of the panel to plug in the mobile standby generator. Mobile standby generator is
not included in this item.

c. Common control equipment: Common control equipment in the panel consists of a voltmeter

(0 to 250 V), a voltmeter selector switch having 4 positions (off/feeder 1/feeder 2/generator
set), a key operated master selector switch for selection of manual or automatic operating
modes, PVC slotted raceway for installation of the control and power wiring, and facility for
installation of the utility metering equipment as required by the regulating authority for
monitoring the total energy consumed by both feeders.

d. Outgoing feeders: Outgoing feeders shall be equipped with a 25 A single pole circuit

breakers for the traffic signal controller, 5 Nos. 10 A single pole circuit breakers for other
traffic related or future systems (e.g. VSS), a 10 A two pole circuit breaker with earthed socket
outlet for local power supply and maintenance/measuring equipment, and a set of neutral
and earth busbars each with twelve numbers of sliding terminals together with insulators and
accessories.

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a. Component Specifications

Specifications for the components mentioned in Article 9.5.2.15 are as follows:

1. Panel housing: Panel housing shall be hot moulded from fibre glass reinforced polyester and

shall be made sturdy by ribbing the rear portion and the door.  The panel housing shall be
IP55  rated.  Enclosure  shall  be  protected  against  dust  deposits  and  shall  be  splash  proof.
Single door shall be equipped with three hinges and shall be locked by a central bolt locking
device with three locking points to ensure that the door is held tight against the housing.  Bolt
closing  system  shall  be  locked  by  means  of  a  rainproof  cylinder  lock  with  a  master  key
system.

2. Moulded case circuit breakers: Moulded case circuit breakers shall be of the thermal

magnetic type and shall be equipped with quick make, quick break, trip free, toggle operated
mechanism to prevent breakers being held in against overloads or faults. Breakers shall
have the characteristics shown in Table 9-10.

Table 9-10: Moulded case circuit breaker characteristics

Rated current

63 A

Delayed thermal over-current release

– 50 A

Instantaneous magnetic release

480 A

Ambient temperature

to 55

. C

Breaking capacity

42 kA at 415 volts, category P2

3. Contactors: Contactors shall be of the magnetic operated type with contact surfaces made

of silver alloy and contact bridges designed to minimize contact bounce and shall induce a
wiping action on contact surfaces to ensure long life with no overdue pitting. The contactors
shall have the characteristics shown in Table 9-11

Table 9-11 Contactor characteristics

Rated operating current

45 A at category AC2 and AC3 duty, 80 A at ACI duty

Insulation rating

660 volts

Permissible temperature

Up to 55

Rated coil voltage

24 V ±10 %

Auxiliary contacts

As required

Rating of auxiliary contacts

10 A

4. Time delay relays: Time delay relays shall be of the electronic delayed pick-up or dropout

type as required in accordance with Table 9-10.

YSTEM

Table 9-12 : Time delay relay characteristics

5. Voltage sensing relays: Voltage sensing relays shall be of the electronic type designed to

monitor the system voltage failure or disturbance to effect the change over command, and
shall be capable of low and overvoltage detection. Relays shall have front knob operated
potentiometers with relevant scale for pick-up and drop-out setting characteristics shown in
Table 9-13.

Table 9-13 : Voltage sensing relay

Insulation rating

250 volts

Rated operating voltage

240 volts

Pick-up setting

80 to 105 % of rated voltage

Drop out setting

5 to 35 % below pick-up voltage

Setting accuracy

±2 %

Permissible temperature

+55

Contacts

1 No. change over contact rated 10 A 250 V AC

Frequency sensing relays:  Frequency sensing relays shall be of the electronic type designed
to  monitor  the  generator  frequency  and  effect  the  changeover  after  the  generator  set  has
reached  its  rated  frequency.    Relays  shall  have  front  knob  operated  potentiometers  with
relevant scale for pick-up and drop-out setting characteristics shown in

Table

9-14 .

Table 9-14 : Frequency sensing relay

Insulation rating

250 V

Operating voltage

240 V

Pick-up setting

90 to 105 % of rated frequency

Drop out setting

0.5 to 2 % below pick-up frequency

Setting accuracy

±0.5 %

Permissible temperature

+55

Insulation rating

250 volts

Rated operating voltage

240 V ±10 %

Permissible temperature

+55

Setting accuracy

±5 %

Time setting range

0.6 - 6 sec. for change over 0.6-6 min. for gen. set
changeover to utility and gen. set cooling

Contacts

1 No. delayed pick-up/drop out contact as applicable.

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Contacts

1 No. change over contact rated 10 A 250 V AC.

6. Manual control switches. Manual control switches shall be of very sturdy construction

designed for semi-flush mounting in 22 mm diameter mounting knock-outs. Contacts
mechanisms shall be designed for bounce free reliable operation, to meet the requirements
of IEC 337-1 and have the following characteristics in Table 9-13:

Table 9-15 : Manual control switch

7. Master selector switch: Master selector switch shall be of very sturdy construction as the

manual control switches and shall be key operated having 2 positions:  Position 1 for auto
control and position 2 for override manual control.  It shall be possible to remove the key only
in the auto position.  The switch shall be as shown in Table 9-14.

Table 9-16 : Master selector switch

Insulation rating

660 V AC

Actuator

Key operated with key removed in auto position.

Contacts

5 sets of each of make before break normally open and
normally closed. contacts

Contact rating

10 A at 240 V AC

Ambient temperature

Up to 60

8. Voltmeter: Voltmeter shall be of the (direct connection) flush mounted type having front

dimensions of 96 x 96 mm equipped with a moving - iron mechanism that has the
characteristics shown in Table 9-15.

Table 9-17 : Voltmeter

Indication range

– 250 V

Accuracy

Class 1.5

Overload capacity

1.2 times continuously, and 2 times for 1 minute

b. Mode of Operation

Automatic transfer dual power supply panels shall be designed to be connected to 2 utility feeders
from different substations as well as to a mobile generator set via the weather proof plug provided
on the side of the panel. Interlocking and operating logic shall perform as follows:

1. Supervise and monitor the voltage level of all feeders and connect one of the two healthy

feeders to the system load. Status of each feeder shall be indicated by the healthy feeder
indication light.

Insulation rating

660 V AC

Actuators

Twist lever operated for the 2 position maintained and
3 position momentary selector switches.

Contacts

Changeover make before break contacts.

Ambient temperature

Upto 60

YSTEM

2. Upon failure of the connected feeder and/or its rated voltage below the pre-set level, the

system logic will transfer the load automatically to the second utility feeder after the pre-set
time delay of 0.6-1 second.

3. In case the mobile generator set is connected (during the scheduled utility maintenance) the

system logic will start the gen. set automatically and connect it to the system load immediately
upon  failure  of  both  utility  feeders.    Upon  restoration  of  any  utility  feeder  the  system  will
monitor  the  feeder  for  the  pre-set  time  delay  (adjustable  between  1-6  minutes)  and  then
transfer the system load to this feeder. Generator will continue to run for a pre-set cooling
time (tem. stabilizing) of 0-2 minutes then shut down automatically.  If the utility feeder fails
again  during  the  cooling  down  time  the  system  will  cancel  the  shut  down  command  and
reconnect the load to the generator.

4. Upon failure of both utility feeders due to a fault on the HT or EHT system which could take

a few hours to restore, the mobile gen. set can be brought to the site and plugged into the
panel which then will start up automatically and perform as described above.

9.5.2.16

Free Right Turn Signal

Free right turn signals shall consist of a signal pole, a complete single aspect signal head, necessary
cabling from the controller to the signal head, and a dedicated flasher unit in the local traffic signal
controller.

Specifications for the components are as described below:

1. Signal pole: Signal pole shall be 3.2 m in overall length and shall be manufactured from a

100 mm inner diameter and 5.4 mm thick structural steel tube and shall be a single piece.
Base plate shall be 16 mm thick and have dimensions of 300 mm x 300 mm.  Pole shall be
welded to the base plate by a continuous deep penetration weld.  Pole shall be closed off at
the top by a pole cap.  Pole shall be galvanized and painted in black and white with suitable
chlorinated rubber or epoxy resin based paint.  Pole assembly (including signal head) shall
withstand 120 km per hour wind velocity plus a 30 % gust factor after installation.

2. Single aspect signal head: Single aspect signal head will display a flashing amber signal.

All components including the housing, signal lamp, reflector, signal lens, visor, etc. shall
comply with all requirements as detailed in Article 9.5.2.8.

3. Cabling: Cabling shall be installed from the flasher unit in the local traffic signal controller to

the signal head of the Free Right Turn Signal. Cable shall comply with all requirements as
detailed in Article 9.5.2.5 .

4. Flasher unit: Flasher unit shall be of heavy duty solid-state type and shall be a dedicated

unit for all the free right turn signals at the intersection. It shall be housed in the local traffic
signal controller. It shall be capable of flashing at a rate of sixty flashes per minute (1 Hz).
Solid-state flashes shall have no contact points or moving parts.

a. Free Right Turn LED Signals and Mounting Accessories

This item shall comply with all requirements of Article 9.5.2.16, except for Clause 2 which is revised
to read as follows:

Single aspect signal head shall display a flashing amber signal. All components including the
housing, LED panel, reflector, signal lens, visor, etc. shall comply with all requirements as detailed
in Article 9.5.2.8.

9.5.2.17

UPS for Traffic Signal Power Back-up System

The design, specification, calculation, manufacturing, testing, shipment, installation and performance
of UPS for Traffic Signal Power Back-up system shall be in accordance with the applicable
requirements of the Owner

’s and as specified herein. The UPS shall be designed to operate

continuously at the specified ambient temperature and humidity with special attention given to the
effects of direct sun-exposure during the day and the occasional sand storms and dusty weather in
designing the enclosure. The UPS shall provide a minimum of 2 hours backup time, at any time

YSTEM

during the operations and maintenance phase. The manufacturer shall guarantee adherence to this
Specification and the performance of UPS under all the required design conditions.

Specifications for the UPS are as follows:

1. Charger: The nominal AC voltage shall be 230V. The input voltage tolerance shall be within

the limit of +20% to -35% with a frequency of 50Hz. Frequency tolerance shall be within
the range of 47-62Hz. The maximum input power shall be selected as per the load connected
with the system. The nominal power factor considered shall be 0.9. The float voltage and
charge voltage shall be selectable. The charger nominal current shall be maximum 10amps.
Maximum heat dissipation shall be 0.6KW.

2. Battery: The nominal Battery voltage shall be 12volt block, 48V string with the following

parameters:

Output voltage at 25

230V AC

Capacity (Ah)

94 Ah Batteries

Number of cells

As necessary

Float temperature compensation :

5mV/deg C/cell

End of discharge voltage

1.75 V/cell

End of discharge current

92A

Charging current

Up to 30A max

3. Inverter: The inverter shall have the following design Parameters:

Nominal Power at 50deg C

: As required with the connected load

Nominal Voltage

: 230V

Nominal frequency

: 50Hz.

Reserve supply nominal

: 48V.Dc

Max. heat dissipation

: 0.6KW

Overload for 5 sec

: >200%

Overload for 10 sec

: >120%

Overload for 3 min.

: >100%

Short circuit of 300% at 50 Hz

: 8ms

Short circuit of 150% at 50 Hz

: 8ms

Output THD

: <3%

Crest factor

: 3:1

YSTEM

The UPS efficiency shall be minimum 95%. Maximum allowable noise level at one meter shall be
48dBA. EMC class shall be FCC level A. The cooling method shall be by two fans with thermostat
controlled. Necessary protection shall be provided against short circuit for the incoming power
supply. The following protection and alarms shall be included in the system:

a)  AC input phase under voltage.
b)  Rectifier failure
c)  DC under voltage
d)  DC over voltage
e)  Charge failure/battery discharging
f)  Battery disconnected
g)  Inverter over current
h)  Inverter failure
i)  Inverter output voltage deviation
j)  Cubicle fan failure
k)  Cubicle/inverter stack over temperature.

Necessary fault and alarm conditions shall be transmitted to the Traffic Management Centre as
directed by the Engineer.

The contractor shall submit detailed shop drawings showing the electrical wiring diagrams for the
UPS. The single line diagram showing the inter connection of the UPS with the Electrical power
supply shall be detailed in the shop drawings.

4. Battery: The battery shall be gel type, valve regulated lead acid. The contractor shall submit

a detailed report on the operating features of the battery such as:

Effect of temperature on service life of the battery.

ii.

Effect of temperature on capacity of battery.

iii.

Effect of temperature on charging current.

iv.

Effect of temperature on charging voltage.

The design life of the battery shall be ten years.
The enclosure shall be glass reinforced polyester, high impact, UV stabilized, fire retardant
with internal metal frame to house UPS and batteries. The protection of the enclosure shall
be IP55 with wall thickness 4mm and point of stress 6mm. The colour shall be plain semi
gloss, light grey, gel coat finish, if not advised by the Engineer. The enclosure doors shall be
able to open 120 degree in fixed position and to be provided with appropriate stopper. The
material submittal shall include details about manual by pass switch, MCB’s, cables and all
accessories for Engineers review and approval.

9.5.3

Construction Requirements

9.5.3.1

Testing, Operation & Maintenance and Training

Testing, compliance and operation & maintenance requirements shall meet the requirements of
Article 9.6.3.1 and Article 9.6.5. Training shall meet the requirements of Article 9.6.5.2.

9.5.3.2

General

Subcontractor  shall  be  responsible  for  the  complete  installation  of  traffic  control  system  at  the
designated  intersections  and/or  interchange,  including  local  intersection controllers,  artery master
controllers, placing intersections under central computer control and all other related components,
materials, equipment, systems and appurtenances.  Subcontractor shall include all labour, materials,
tools, equipment and appurtenances and shall perform all work required to complete the installation,
to the approval of the Engineer, of the traffic control system.

YSTEM

9.5.3.3

Location of Equipment

Equipment and components of the traffic control system shall be located as shown on Contract plans,
and in accordance with the requirements of the intersections and/or interchanges and relationship
of various subsystems and the various control systems.

The Subcontractor shall verify the locations of all traffic control system equipment

with the Engineer’s

representative, as well as the final locations of all foundations, conduit and similar work installed or
being installed under the various roadway contracts.

9.5.3.4

Installation

Subcontractor shall be responsible for the complete installation of all wiring, distribution of power
from the power source to the control foundation and to all equipment and components of all systems,
the specified components of the traffic control system with all subsystems, control systems, and all
related work as specified herein, as required for the complete installation, and as approved by the
Engineer.

Subcontractor shall contact the electrical authority to arrange for 3 phase, 415v/240v, 4-wire, 50 Hz
electrical supply for the controllers and all related traffic control system equipment. Two sources of
power supply are required for the automatic transfer dual power supply panel at each
intersection/interchange that will be signalized.

Subcontractor  shall  comply  with  the  requirements  of  the  electrical  authority  for  the  service
connection.    There  shall  be  no  separate  payment  for  the  service  connection.    Cost  of  service
connection  work  shall  be  an  incidental  part  of the  bid  prices  of  other  items  of  work  in  the  Bills  of
Quantities.

Unless otherwise approved by the Engineer  in writing, no installation shall take place without  the
Engineer's presence and supervision.  Such presence and supervision of the Engineer shall in no
way  relieve  the  Subcontractor  from  his  responsibility  of  installing  the  traffic  control  system
components properly and according to proven engineering standards and practices so that the traffic
control system will function and operate to the satisfaction of the Engineer after installation.

If the Engineer determines, as the sole judge of such determination, any time prior to the issuance
of  the  written  final  acceptance  certificate,  that  any  subsystem,  equipment  component  part  and/or
appurtenance  of  the  traffic  control  system  is  improperly  installed  or  not  fully  compatible  with  the
existing  traffic  control  system,  such  subsystem, equipment,  component part  and/or  appurtenance
shall be removed and reinstalled, with new parts and components if necessary in the judgment of
the Engineer, by the Subcontractor at his own expense.

9.5.3.5

Performance Evaluation

Each  item  included  under  this  Project  including but  not  by  way  of  limitation  all  poles,  mast  arms,
signal heads, controllers, detectors, control systems, communication hardware and all other related
equipment,  components  and  materials  shall  be  subjected  to  actual  performance  evaluations  if
required  by  the  Engineer  and/or  the  Owner.    For  this  purpose,  the  Subcontractor  shall  submit
samples  or  prototypes  of  each  type  of  major  equipment  and  component,  construct  prototype
conditions  for  field  and/or  laboratory  testing  as  specified  and  as  directed  by  the  Engineer.
Components  and  subsystems  shall  be  approved  by  the  Engineer  before  equipment  and  system
manufacturing and assembly.

9.5.3.6

Reliability Requirements

Equipment and components employed in the traffic control system shall meet stringent requirements
on reliability and mean-time-before-failure.  Subcontractor shall employ good design practices and
design equipment and components for long life.  Subcontractor shall furnish satisfactory evidence
that  multiple  sources  of  supply  are  available  for  components  and  equipment  as  directed  by  the
Engineer.   Equipment  and  components  shall  be  designed for  ease  of maintenance  with  as  much
modularity and parts commonality as feasible.

Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020) - page 52