TRAFFIC SIGNS AND ROAD MARKINGS
GENERAL
The purpose of traffic signs is to promote road safety and efficiency by providing for the orderly movement of all road users on all roads in both urban and non-urban areas. Traffic signs notify road users of regulations and provide warning and guidance needed for reasonably safe, uniform and efficient operation.
To be effective, a traffic sign should meet five basic requirements:
Design, placement, operation, maintenance, and uniformity are aspects that should be carefully considered in order to maximise the ability of a traffic sign to meet these five basic requirements. The decision to use a particular sign at a particular location should be made on the basis of traffic engineering study.
1. CLASSIFICATION OF TRAFFIC SIGNS
Traffic Signs are broadly classified as mandatory, cautionary and informatory signs.
1.1 Mandatory/regulatory signs
These signs inform the road users about certain laws and regulations to be followed, to provide a safe and free flow of traffic. The violation of these signs is a legal offence.
These signs are classified under the following six sub-heads:
1.2 Cautionary/warning signs
These signs warn the road users about any hazard on or adjacent to the roadway. These signs are in the shape of an equilateral triangle 90 cm or 60 cm, with apex pointing upwards. The sides have a red border 70 mm wide for 90 mm size boards and 45 mm for 60 cm size boards. In non-urban areas, the warning signs should be located at the distances shown in table 2800-1 in ahead of the hazard location.
Recommended locations for installing warning signs in non-urban roads.
Class of road |
Plain / rolling terrain |
Hilly terrain |
National & State Highways |
120 m |
60 m |
Major District Roads |
90 m |
50 m |
Other District Roads |
60 m |
40 m |
Village Roads |
40 m |
30 m |
In urban areas, the warning signs should be located at about 50 m ahead of the hazard location.
1.3 Informatory/guide signs
These signs are used to guide road users about destination and distance, useful information etc to make the travel safe, easier and pleasant.
The informatory signs are classified under the following sub-heads:
The colour, configuration, size and location of all the traffic signs for highways other than Express ways shall be in accordance with the code of practice for road signs, IRC:67 or as shown on the drawings. For expressways, the size of the signage, letters and their placement shall be as specified in the contract drawings and relevant specifications or as directed by the Engineer.
2. MATERIALS FOR TRAFFIC SIGNS
2.1 Concrete
Concrete shall be of M15 grade as per section 600 of this Manual or as specified in the contract Drawings.
2.2 Reinforcing steel
Reinforcement steel shall conform to the requirements of IS: 1786 or as specified in the contract Drawings.
2.3 Bolts, nuts and washers
High strength bolts shall conform to IS: 1367 whereas precision bolts, nuts etc shall conform to IS: 1364.
2.4 Plates and supports
Plates and support sections for the sign posts shall conform to IS: 226 and IS: 2062 or any other relevant IS Specifications.
2.5 Sign panels
Sign panels shall be fabricated on aluminium sheet, aluminium composite panel, fibre glass sheeting or sheet moulding compound.
Aluminium composite material (ACM) sheets used for sign boards is a sandwiched construction of a thermoplastic core of low density polyethylene (LDPE) between two thick skins/sheets of aluminium 0.5 mm or 0.3 mm on both sides.
The required mechanical properties of ACM and that of aluminium skin are given in table 800-1 of MoRTH Specifications for Road & Bridge works (5th Revision 2013).
3. TRAFFIC SIGNS HAVING RETRO REFLECTIVE SHEETING
The retro-reflective sheeting used for sign boards consists of white or coloured sheeting, having a smooth outer surface which has the property of retro-reflection over its entire surface. The retro-reflective sheeting shall be either of engineering grade material with enclosed lens, high intensity grade with encapsulated lens or micro-prismatic grade retro-reflective element material. The guidance on the recommended application of each class of sheeting may be taken from IRC: 67.
3.1 Classes of retro-reflective sheeting
Retro-reflective sheeting is divided into three classes as follows:
The class of the sheeting to be used will depend upon the type, functional hierarchy and importance of the road. The recommended applications for retro-reflective sheeting as per IRC: 67-2010 is given in table.
Table: Recommended applications for retro-reflective sheeting
Sheeting type |
Category of road |
||||
National / State Highways |
Major Dist. Roads |
Rural Roads |
Urban Roads |
Expressways |
|
Class A (Type I and II) |
- |
- |
√ |
- |
- |
Class B (Type III and IV) |
√ |
√ |
√ |
√ |
- |
Class C (Type VIII, IX and XI) |
√ |
- |
- |
√ |
√ |
*Type III sheeting is available both as glass beaded and micro prismatic technology as per ASTM D 4956-09. The light reflecting efficiency of glass beaded sheeting is lower than the micro prismatic sheeting.
NOTE: The authority for selecting type of sheeting between classes or within a class is vested with the client.
3.2 Class A retro-reflective sheeting
3.2.1 Engineering grade (Type I)
This sheeting shall be of enclosed lens glass bead type consisting of microscopic lens elements embedded beneath the surface of a smooth, flexible, transparent, water-proof plastic, resulting in a non-exposed lens optical reflecting system.
The retro-reflective surface after cleaning with soap and water and in dry condition shall have the minimum coefficient of retro-reflection (Determined in accordance with ASTM D 4956 - 09) as indicated in table 6.3 of IRC: 67-2010.
3.2.2 Super engineering grade (Type II)
This sheeting is similar to type I but with higher level of retro-reflective properties as (Determined in accordance with ASTM D 4956 -09) as indicated in table 6.4 of IRC: 67-2010.
3.3 Class B High intensity grade sheeting
3.3.1 High intensity grade sheeting (Type III)
This high intensity retro-reflective sheeting shall be of encapsulated lens type consisting of spherical glass lens, elements adhered to a synthetic resin and encapsulated by a flexible, transparent waterproof plastic having a smooth surface or as an unmetallised micro-prismatic reflective material element.
The retro-reflective surface after cleaning with soap and water and in dry condition shall have the minimum co-efficient of retro-reflection (Determined in accordance with ASTM D 4956-09) as indicated in table 800-2 of MoRTH Specifications (Ref: Table 6.5 of IRC: 67-2010).
When totally wet, the sheeting shall show not less than 90% of the values of retro reflectance, indicated in table 800-2.
At the end of 7 years, the sheeting shall retain at least 80% of its original retro-reflectance.
3.3.2 High intensity micro-prismatic grade (HIP) sheeting (Type IV)
This sheeting shall be of high intensity retro-reflective sheeting made of micro-prismatic retro-reflective element material coated with pressure sensitive adhesive.
The retro-reflective surface after cleaning with soap and water and in dry condition shall have the minimum co-efficient of retro-reflection (Determined in accordance with ASTM D 4956-09) as indicated in table 800-3 of MoRTH Specifications (Ref: Table 6.6 of IRC: 67-2010).
When totally wet, the sheeting shall show not less than 90% of the values of retro reflectance, indicated in table 800-3.
At the end of 7 years, the sheeting shall retain at least 80% of its original retro-reflectance.
3.4 Class C Micro-prismatic grade sheeting
3.4.1 Micro-prismatic grade sheeting (Type VIII)
This is a reflective sheeting typically manufactured as a cube corner. The reflective sheeting shall be retro-reflective type, made of micro-prismatic retro-reflective material.
The retro-reflective surface, after cleaning with soap and water and in dry condition shall have the minimum co-efficient of retro reflection (Determined in accordance with ASTM D 4956-09) as indicated in table 800-4 of MoRTH Specifications (Ref: Table 6.7 of IRC: 67-2010).
When totally wet, the sheeting shall show not less than 90% of the values of retro reflectance, indicated in table 800-4.
At the end of 10 years, the sheeting shall retain at least 80% of its original retro-reflectance.
3.4.2 Micro-prismatic grade sheeting (Type IX)
This is a retro-reflective sheeting similar to Type VIII but with higher level of retro-reflective characteristics as indicted in table 800-5 of MoRTH Specifications (Ref: Table 6.8 of IRC: 67-2010).
3.4.3 Micro-prismatic grade sheeting (Type XI)
This is a retro-reflective sheeting similar to Type IX but with higher level of retro-reflective characteristics as indicted in table 800-6 of MoRTH Specifications (Ref:Table 6.9 of IRC: 67-2010).
4. Materials
5. ROAD MARKINGS
Road markings are defined as lines, patterns, words or other devices, except signs applied or attached to the carriageway for controlling, warning and guiding and informing the users. Road markings perform an important function of guiding and controlling traffic on a highway. They can also be applied in other facilities used by vehicles to mark parking spaces or designate areas for other uses.
Road markings shall be uniform in design, position and application so that they may be recognised and understood immediately.
6. MATERIALS FOR ROAD MARKING
Road markings shall be of ordinary road marking paint, hot applied thermoplastic compound, reflectorised paint or cold applied reflective paint as specified in the item and the material shall meet the requirements as specified in Clause 803 of MoRTH Specifications.
6.1 Ordinary road marking paint
Table: Properties of constituents in road making material
Component |
White |
Yellow |
Binder |
18% Min |
18% Min |
Glass beads |
30% to 40% |
30% to 40% |
Titanium dioxide |
10% Min |
Manufacturer’s option |
Calcium carbonate & inert fillers |
42% Max |
Manufacturer’s option |
Table: Properties required for thermoplastic material
Property |
Code |
White |
Yellow |
Luminance |
AASHTO 249 |
65% Min at 450 |
45% Min at 450 |
Drying time |
- |
15 minutes max |
15 minutes max |
Skid resistance |
BS 6044 |
Not less than 45 |
|
Cracking resistance (At low temperature) |
- |
No cracks on application to concrete blocks |
|
Softening point |
ASTM D 36 |
102.5°C ± 9.5°C |
|
Yellowness index |
AASHTO 249 |
Not more than 0.12 |
|
6.1 Requirements for glass beads
The glass beads shall meet the grading requirements given in table. (Ref:Table 800-10 of MoRTH Specifications).
6.2 Cold applied reflective paint
In this method, traffic stripes are marked using a solvent based cold applied paint, which shall be applied on the asphalt/cement concrete road surface by brush or by spray equipment capable of spraying the paint on the road (Road marker). Glass beads shall be subsequently spread pneumatically on to the paint, when it is still wet, so that the beads will be firmly held by the paint after drying.
6.3 Requirements
The colour of the paint shall be white or yellow (IS colour No. 356).
The cold applied paint material shall be homogeneously composed of binder, pigment, extenders and other additives as required for the formulation.
The pigments and extenders shall be uniformly dispersed in the binder medium dissolved in organic solvents.
Table: Properties of constituents of paint.
Component |
% by weight |
|
White |
Yellow |
|
Binder |
25 (Min) |
18 (Min) |
Titanium dioxide |
20 (Min) |
- |
Calcium carbonate & inert fillers |
16 (Min) |
29 (Min) |
Yellow pigments |
- |
14 (Min) |
Table: Retro-reflective properties required s
Property |
Specification |
|
White |
Yellow |
|
Coefficient of retro-reflection (On application) |
300 mcd/m2/lux |
200 mcd/m2/lux |
Coefficient of retro-reflection |
100 mcd/m2/lux |
100 mcd/m2/lux |
(After defect liability period of one year) |
100 mcd/m2/lux |
80 mcd/m2/lux |
6.4 Sampling and testing
7. REFLECTIVE PAVEMENT MARKERS (ROAD STUDS) AND SOLAR POWERED ROAD MARKERS (SOLAR STUDS)
7.1 Reflective pavement markers (Road studs)
7.2 Requirements
7.3 Sampling and testing
7.4 Solar powered road markers (Solar studs)
RELATED CODES :
1. MoRTH Specifications for Road and Bridge works, 5th Edition 2013 – published by IRC, New Delhi.
2. IRC-SP: 11 Quality control for the construction of roads and runways.
3. IRC: 67 Code of practice for road signs.
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