The document provides specifications and best practice guidelines for variable message sign (VMS) installations on motorways and freeways. It outlines requirements for the expected life, display properties, environmental protection, structural integrity, and electrical components of VMS signs. Requirements include a minimum 7-9 year life, IP55 water and dust protection rating, support for various fonts and languages, and redundancy measures like uninterruptible power supplies.

1. VMS Specifications & Best Practice Design Guide:
Document Controls
Document Title VMS Specifications & Best Practice Design Guide Document Use Public Use
Dociument Date 1/10/2012 Document State Current
Document Version 0.01 Document Expiry 1/06/2013
Document Author Dave Verma Document URL
Abstract
Motorway or Freeway VMS signs are typically large scale installations mounted on a gantry structure which spans a number of lanes.
Traditionally these devices have been constructed from conventional steel housings that utilise Light Emitting Dide (LED) based
technologies and associated supporting controllers and other infrastructure internally in the sign to produce illuminated messages for
motorists. These messages are typically driven from a traffic management system.
Increasingly the need to be able to display pictograms as opposed to text messages and in more than one primary colour has resulted in
substantial effort and investment from VMS sign manufacturers . The advantage of these images is that they cross language barriers and
literacy and provide instant information absorption for motorists whom might not process text otherwise.
The other ob vious benefit lies with the ability of the sign to also disply more colours shapes and graphics in line with consumer
expectations around technology advancements and the requirement of roading authorities to deliver higher impact public messages.
The use of large collections of outdoor hardened LCD panels will eventually replace the LED approach being used today - signs which have
modules which are effectively LCD panels will result in higher resolution text and images potentially adding value to transport authorites
for sporting and cultural event advertising in addition to public messages. This technology is immature at present. Irrespective of the
displayt element the basic structures and needs will remain the same.
Motorway/ Freeway VMS Sign Requirements
Expected life of motorway VMS 7-9 years
Expected mean time between failures 1 event in every 10,000 hours or 150,000 hours per LED or LEE pixel
Character height At least 400mm for overhead mount or side mount with <6m offset
(450mm is required for side mount with >6m offset)
Number of pixels across Minimum 124 pixels per line
Number of pixels vertically Minimum 30 pixels
Number of lines of characters 3 lines - minimum for text all full text - note for pictographical applications this value is irrelevant and needs to be evaluated based on size of desired image
Pixel configuration Full matrix
Display font / pixel spacing. Dependant on NTCIP MIB and Character Heights as well as Language and or requirements for Pictograms
Lanterns Optional TBA The use of external flashers is gradually being reduced and is not encouraged
Visual performance In accordance with EN 12966-1
Beam width EN 12966-1. Class B2. (Corresponds to 14o minimum total angle - ideally this should be upto the maximum width
supported at full luminence 20o is typically a better result i.e approaching class B5 of the standard)
Display colour EN 12966-1. Class C1 (Corresponds to Amber - in the case of RGB mix situations the issue becomes one of subjective assessment of saturation eveness)
Display Flicker rates No greater than 0.16 milliseconds. Emitted light shall have a frequency of not less than 90 Hz.
Display Intensity Display Intensity should be governed in timed steps based on the outputs of at least two (2) light sensors located on the VMS in locations where
such sensors and detection process are not subject to short term lighting fluctuations and provide the right ambient detection balance. Luninosity should be steppable up or down
within a range of at least 180 increments
Pixel arrangements Pixels may be arranged either with a single high output LED / OLED and lenses or by grouping LED's or by use of LCD elements or OLED elements
Display Modules All Pixels are to be arranged on modular easily replaceable blocks "Display Modules" which can be 'hot plugged" in or out without tools.
Display Refreah The time to display a message or any other pictogram shall be less than .5 of a second from blank
Component standards All surface mount components will be wave soldered. The use of conformal coatings to protect PCB units and surface mount components is encouraged.
Luminance EN 12966-1. Class L3
Luminance ratio EN 12966-1. Class R3.
Front of display cover UV stabilised polycarbonate >4mm thickness or not required if using optical LED enhancements, or conformally coated pixels, typically a drilled mask is preferable
Impact Test requirements Depends on Environmental conditions - note sandstorms will require different treatment than high humidity
Display to be shaded Internal louvers or drilled external galvinised mask painted or coated in black
Bezel width Minimum 300mm 5.1.1 Minimum 300mm where there is not a requirement for edge to edge displays i.e displays mounted on other signage or backed by sympathetic block colours
Colour of enclosure Front including bezel: Matt black

2. Rear top bottom and sides: Semi gloss aircraft grey or light beige/blue
Environmental protection EN 12966-1. Class T1. (Corresponds to operational range of -15oC to +60oC)
Ingress protection EN 12966-1. Class P2. Water (Minimum IP55) & EN 12966-1. Class D3. Dust and other pollutants
Fonts The VMS shall display both proportionally spaced or non proportionally spaced left, center and right justified fonts and will allow
(based on Language) a full set of upper and lower case characters to be displayed
Enclosures & Sign Attributes
Enclosure structure The VMS enclosure shall be constructed from rigid materials preferably aluminium treated
with anticorrosive agents or coated in an UV stablised material. The use of rigid high impact thermo plastics
is not encouraged for structural elements but may be used for coatings
or other areas of non structural build. The use of carbon fibre for sign enclosures is not encouraged due to maintainability requirements.
Enclosure Mounting The VMS enclosure is to be treated as an integral part of the Gantry for load bearing and structural reasons. This approach requires that mounting points
for the VMS shall be arranged such that once installed the VMS is an integral part of the proposed gantry structure and directly contributes to its strength
Environmental Weathering There should be no impact on structural integrity or visual appearance (including colour fading or corrosion) of the
enclosure due to Environmental or Particulate exposures for the expected life of the sign. Any contact between untreated, dissimilar metals
is not acceptable
Harmonic Resonance and Vibration The equipment mounted in the sign must be able to withstand significant continuous harmonic vibration as well as sudden acceleration -ve and +ve arising from wind gusts
The manufacturer will provide test results from an indpendant laboratory to certify that the sign has been subjected to extensive vibration testing.
Structure - Lift points and Rigidity A minimum of two lifting points on the sign are to be used when mounting the sign onto the respective gantry. Four lifting points are recommended
Structural Integrity is a critical factor and calculations for wind loading and enclosure rigidity during lift and installation as well as normal operations are expected.
Structure - access to VMS enclosure The gantry design shall eliminate or minimise the need for a lane closure during maintenance
Access Doors Where enclosures are of a ‘walk-in type’, two access doors are to be provided for entry, one at each end of the sign, doors are to be secured with locks and seals
that allow air pressure to be maintained inside the sign and prevent thermal exchange or exhange of untreated air.
Access Doors will have a ‘stay’ to retain the door in the open position for the safety of maintenance personnel working inside the enclosure.
Access Doors will be alarmed.
Facia Viewing Angle For signs mounted over 5m above the roadway with a desired viewing angle of a minimum of 15o the facia should be angled downwards between 3o and 5o.
Facia Impact Requirements Impact testing requirements, the sign facia must be able to meet the the EN 60 598-1 Impact Test as described in EN 12966-1:2005
Alternatives to meeting this requirement may be considered if these have demonstrably been tested by an independent laboratory such as METAS.
Electronic components and mounting All electronics and related modular components must be easily accessible and removable by hand without tools for
maintenance purposes. All electrponics that relate to the display should be hot swappable and pluggable including power supplies
A modular rack type mounting framework shall be installed within the sign to facilitate the mounting of display elements.
Access Points (cables and services) All access points into the sign for all cables are to be sealed and glanded without exception. No cables are to be visible on the outside of the sign
Air Management Untreated air is not to be circulated within the sign. The use of airconditioning is to be avoided in preference to the use of electromagnetic cooling units mounted every 3m
The components used to make up the electronics and materials in the sign are to be rated at a minimum heat tolerance of -5 to +65o Centigrade
All air is to be filtered before entering or exiting the sign, The ventilation system should be electrically fan driven based on thermostatic monitoring of a base temperature exceeding 40o Centigrade
Internal Lighting & Inspection facilities LED light fittings are to be installed for inspection purposes - these should produce the equivalent output to at least a 100 watt light bulb and should be spaced every 2 m.
A minimum of six single-phase switched 10A 250 v AC rated power outlet sockets, are to be provided in the sign for the connection of diagnostic laptops, tablets etc
Multiplug type power sockets are to be used
Specific Environmental Requirements The equipment located within the enclosure shall be protected from moisture, dust, dirt, corrosion and insects.
The enclosure shall provide a minimum IP55 ingress protection as described for Class P2 in Table 16 of the
European Standard EN 12966-1.
The enclosure shall provide ingress protection against dust, particulates,sand and pollen and other pollutants as described for
Class D3 in Table 17 of the European Standard EN 12966-1.
Temperature Range in excess of Class T1 in EN 12966-1 Table 8.
This range corresponds to a minimum temperature of -15oC and a maximum of +60oC.
For Middle Eastern Applications a maximum internal cabinet temperature of 70oC is required with auto shutdown
The display cabinet shall include a treated air venting and/or air-cooling system to ensure the manufacturers
recommended maximum operating temperature or humidity conditions are not exceeded. All fans and other
forced air devices shall be thermostatically controlled and use standard-size removable filters.
AC is not recommended the use of electromagnetic cooling devices and heat exchnagers are to be encouraged
As far as practicable the design shall ensure that no untreated/unfiltered external air is able to come into contact
with any electronic equipment within the sign.
In order to operate in the specified temperature range, consideration must be given to preventing the
accumulation of condensation. This may be achieved as a direct resultof venting air through the sign
and reusing heat being generated from power supplies.

3. Weep holes must be provided to allow the drainage of any water that may collect in the display cabinet and a
suitable moisture inhibitor may be used. Weep
Weep holes shall be positioned and protected to prevent ingress of volumes of air or other materials, and be fitted with insect mesh.
Field Device Controller A field control device (FCD) located at each VMS site shall be capable of operating the sign in both local control
mode (i.e. no external communications) and remote control mode (communicating with an external central
control system). This device shall have USB connectors and RJ45 connectivity and support a TCPIP stack both DHCP and Static addresses
This controller must support NTCIP (NTCIP 1203 for dynamic message signs) and present SNMP alerts and traps.
The VMS FCD shall provide the electronics necessary to:
SNMP • Receive and issue SNMP commands from/to the central control system.
• Communicate using SNMP commands over Ethernet TCP/IP protocols; Serial tunnelling (PMPP -RS232 to Ethernet)
devices for primary control are not permitted.
• Control the display of messages on the sign.
Alerts & Alarms • Report errors to the central control system.
• Receive direct manual instruction from vendor proprietary PC software (local or remote).
The FCD shall support NTCIP in accordance with the large DMS 1203 MIB.
The FCD shall have sufficient memory to store a minimum of 150 message strings for immediate display upon
command from the VMS master or local control that could include operating from a timer. The controller shall
also have sufficient RAM memory to upload and download non-library messages. Graphics must be supported
in the field controller.
The FCD shall incorporate a watchdog timer to detect an out-of-program condition and reset the controller.
Additionally, a remote reboot function would be required based on input from watchdog timer or other inputs,
local or remote.
Failsafes The FCD shall be designed for fail-safe prevention of improper information display in the case of malfunction. As
a minimum, this shall include the ability of an automatic blanking feature, which immediately clears the message
displayed on the sign in the event of internal or external failures such as a communications failure with the
central control system, invalid transmission from the VMS control system, or power failure.
In local control mode (no external communications), the FCD shall have as a minimum: operator selection of
dimming levels, operator selection of pre-stored messages, and diagnostic routines capable of testing full sign
operation.
The local control shall be accomplished by using a menu-driven LCD display
The FCD shall be provided with an interface for plugging in a laptop computer
for configuration, diagnostic testing and downloading/uploading messages.
Interfaces RJ45 Ethernet TCPIP / Secure Wireless LAN - N /USB for message set uploads and rs232 for terminal commands.
Router A router will be provided which allows for the attachment of upto 3 TCPIP CCTV cameras to the sign and its communications systems.
UPS The VMS will be equipped with an uninterruptible power supply (UPS) , which shall maintain the operating state of the sign for at least 4 hours
and the operation of the controller and communications equipment for a minimum period of six hours in the event of total power loss
Mulitple UPS units may be used to achieve this one set for the electronics and comms and one set for the display
Power to the VMS controller and communications equipment shall be routed via the UPS to ensure a clean and
stable power supply.
The use of LION battery packs is encouraged to minimise weight vendors should consider mounting battery banks in the Gantry legs for ease of access and serviceability
as well as preventing excessiveweight in the sign enclosure itself.
Sundry Electrical Requirements All display equipment shall be internally protected against damage resulting from:
• Lightning strikes near the VMS/gantry/roadside cabinet
• Electrical transients on power cabling
• Electrical transients on internal and external signal wiring
• Electromagnetic interference
• Static electrical discharge.
A lightning protection system shall be installed in accordance with NZS/AS 1768-1991. The system shall consist
of:
• Air termination to intercept lightning discharges directly.
• Down conductors to connect the air terminal to earth terminals. Note that it is possible that these down

4. conductors can be formed from reinforcing steel that may be used in concrete support structures (as
applicable).
• Earth terminations to discharge the lightning currents into the general mass of earth. Note that this may in
part, or in full, consist of the foundations for the support structure, depending on the calculated required
maximum earthing resistance.
• Equi-potential bonding between the lightning earthing system and any other earthing systems for personal
and equipment protection.
Multi-stage surge diversion shall also be provided on the incoming power circuits and communication circuits.
Surge diverters shall be field replaceable without the need to disconnect wiring and they shall have integral
indicators to show when they have blown (as applicable). A preferred option is to have an auto-reset function
which negates the need for an actual site visit.