Continuous signs

2.5.1 Different types

Continuous signs are divided into the following two main types:

• Mechanically variable signs (prism signs)

• Two-position signs

– Position change by means of voltage/current (e.g. Dulf, LCD) – Position change by means of mechanical/manual operation Mechanically variable signs (prism signs)

The message on the sign is varied by rotating the necessary number of prisms, where each prism side has a different message. Signs that are constructed so that each message is distributed over several parallel prism sides can be equipped with several motors. The motors shall then be synchronised.

The sign’s total front panel shall not have significantly larger outer measurements than a fixed sign of a corresponding type.The motor must be strong enough to tolerate normal Norwegian winter conditions, but the sign shall be assembled with a safety mechanism that stops rotation if foreign bodies come between the prisms.

The motor’s speed shall if necessary be variable to enable precise stops when positions are reached. The speed shall enable changes to the sign message within maximum 5 seconds.

If the electricity fails, it must be possible to rotate the prisms manually.

The sign motor and prisms shall not be pla-ced in the same space. The space where the motor is located shall be easily accessible by means of a separate door/hatch. Terminal blocks for terminating external and inter-nal wires/cables can be placed in the motor space or in a separate switch cabinet.

Controllers shall be placed outside the sign and column.

To ensure that letters and symbols appear coherently, the space between two adjacent flat elements (prisms) of the sign face shall

not be greater than 5% of the diameter of the Figure 2.8 Example of a mechanically variable sign/prism sign (with outside lighting).

largest circle that can be drawn using the points of the prism element, and maximum 12 mm.

Cf. figure 2.9.

When changing a sign’s position (command), the controller shall monitor the response from the position transmitter. Deviations of maximum

± 7° shall be accepted by the controller. If the correct response does not appear within a pre-

defined time (e.g. 5 seconds), the status exit for ERROR shall be activated. The exit shall remain active until the error is corrected independently of the sign’s position.

Sign lighting shall be designed and installed so that road users are not dazzled. If the ligh-ting fitligh-ting contains several light sources, it shall be connected in such a way that not all light sources are extinguished because one source is faulty.

If the sign is equipped with a front screen, the light fitting may be placed behind the screen.

The design of the messages for continuous signs shall, with the exception of the breaks in the message surface that the structure itself entails, be based on the Norwegian Road Administration’s Manual 050 Trafikkskilt [Road traffic signs] and 053 Bruk av variable trafikkskilt [Use of variable road traffic signs].

Two-position signs

For signs that change position by means of voltage/current, the sign’s front plate when turned off shall appear as a neutral grey surface, with no visible message. Activating the sign’s message is done by turning on the voltage/current.

In the event of electricity failure, it must be possible in the case of a curtain sign to rotate the curtain manually.

Figure 2.9 Distance between adjacent flat elements.

Figure 2.10 Two-position sign in active and passive positions.

The space where the motor is placed shall be easily accessible by means of a separate door/

hatch. Terminal blocks for termination of external and internal wires/cables shall be easily accessible.

For signs that change position by means of a mechanical or manual operation, the sign’s front plate in a closed position shall appear as a neutral grey surface, with no visible message.

In general: for all light-emitting two-position signs, the number of light sources shall be adapted to the size of the sign, so that luminance is even over the entire sign face.

2.5.2 Visibility requirements

Visibility requirements for continuous signs are the same as for fixed signs, and the traffic alphabet shall be used. With respect to requirements for sign sheeting, reference is made to Part 1 of this manual and NS- EN 129899-1. This applies to both selection of correct she-eting class, requirements for retroreflection, colours and luminance factors.

For light-emitting, continuous signs, there are requirements relating to luminance level, luminance contrast and luminance evenness. The requirements are found in Part 1 of this manual.

Variable road traffic signs shall show a sign surface that is the same size as the normal pro-visions dictate for the fixed version of the sign in question. For signs with text, the neces-sary reading distance and text height shall be assessed and decided in the same way as for fixed signs. For these normative provisions, reference is made to Manual 050 Part 1, Appendix 1.

Variable message road traffic signs that provide messages other than those that are standar-dised for fixed road traffic signs fall under sign 560 “Information sign”. Part 3 of Manual 050 addresses text heights and dimensions for this sign in particular (refer also to Manual 050 Part 1, Appendix 1).

2.6 References

• FOR 1993-12-14 Forskrift om kvalifikasjoner for elektrofagfolk [Regulations concerning the qualification of electro professionals]

• FOR 1995-08-10 Forskrift om kvalifikasjoner for elektrofagfolk [Regulations concerning electronic equipment]

• FOR-1998-11-06-1060 Forskrift om elektriske lavspenningsanlegg [Regulations concerning electric low-voltage systems]

• NS EN 12966-1:2005 Road traffic vertical signs - Variable message traffic signs – Part 1: Product Standard

• NS-EN 12899-1 Fixed, vertical road traffic signs - Part 1 Fixed signs, 2007

• NEK IEC 60417 Graphical symbols for use on equipment

• NEK IEC 60529 Degrees of protection provided by enclosures (IP code)

• NEK IEC 61346 Industrial systems, installations and equipment and industrial products - structuring principles and reference designations

• NEK IEC 60617 Graphical symbols for diagrams

• NEK EN 50293 Electromagnetic compatibility - road traffic signal systems - product standard

• NEK EN 60439-1 Low-voltage switchgear and controlgear assemblies.

Part 1: Type-tested and partially type-tested assemblies

• Manuals 050 Trafikkskilt (skiltnormal) [Road traffic signs (the sign standard)]

Directorate of Public Roads, 2007/08)

• Manual 053 Bruk av variable trafikkskilt [Use of variable message road traffic signs] (Directorate of Public Roads, 2004)

• Manual 111 Drift og vedlikehold [Operations and maintenance]

(Directorate of Public Roads, 2003)

• The Standards Norway website: www.standard.no