08-ROAD MARKINGS

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:

1. Fulfill a need.
2. Command attention.
3. Convey a clear, simple meaning.
4. Command respect from road users.
5. Give adequate time for proper response.

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. ‘Stop’ and ‘Give way, signs.
2. ‘Prohibitory’ signs.
3. ‘No parking’ and ‘No stopping’ signs.
4. “Speed limit’ and ‘Vehicle control’ signs.
5. ‘Restriction ends’ sign.
6. ‘Compulsory direction control’ and other signs.

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.

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:

1. Direction and place identification signs.
2. Facility information signs.
3. Other useful information signs,
4. Parking signs.
5. Flood gauge.

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:

1. Class A sheeting: Engineering and super engineering grade sheeting as per ASTM D 4956-09 type I and II.
2. Class B sheeting: High intensity and high intensity prismatic grade sheeting as per ASTM D 4956-09 type III and IV.
3. Class C sheeting: All micro-prismatic grade sheeting as per ASTM D 4956-09 type VIII, IX and XI.

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

*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)

1. 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.

2. 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)

1. 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.

2. 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).

3. When totally wet, the sheeting shall show not less than 90% of the values of retro reflectance, indicated in table 800-2.

4. 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)

1. This sheeting shall be of high intensity retro-reflective sheeting made of micro-prismatic retro-reflective element material coated with pressure sensitive adhesive.

2. 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).

3. When totally wet, the sheeting shall show not less than 90% of the values of retro reflectance, indicated in table 800-3.

4. 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)

1. 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.

2. 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).

3. When totally wet, the sheeting shall show not less than 90% of the values of retro reflectance, indicated in table 800-4.

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

1. Aluminium alloy or galvanized steel to be used as truss design supports shall conform to the relevant IS.
2. After steel trusses have been fabricated and all holes punched, they shall be galvanized.
3. When aluminium sheets are used for road signs, they shall be smooth, hard and corrosion resistant conforming to IS: 736. The minimum thickness of sheet shall be 1.5 mm.
4. High strength bolts shall conform to IS: 1367 whereas precision bolts, nuts etc shall conform to IS: 1364.
5. Plates and support sections for the sign posts shall conform to IS: 226 and IS: 2062 or any other relevant IS Specifications.
6. The overhead signs shall be of micro prismatic retro-reflective sheeting. In the absence of details or for any missing details in the contract documents, the signs shall be provided as directed by the Engineer.

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

1. Ordinary paint used for road marking shall conform to Grade 1 as per IS: 164
2. The materials shall be free from all skins, dirt and foreign objects and shall comply with the requirements given in table .(Ref: Table 800-9 of MoRTH Specifications).

Table: Properties of constituents in road making material

3. The  colour  of  the  compound  shall  be  white  or  yellow  (IS  colour  No.  356)  as specified in the Drawings or as directed by the Engineer.
4. The  properties of white/yellow  thermoplastic  material when tested in accordance with ASTM D 36/ BS-3262 (Part1) shall be as given in table.
5. The thermoplastic material shall meet the requirements for a shell life period of one year. Any material not meeting the above       requirements shall be replaced by the manufacturer/supplier /contractor.

Table: Properties required for thermoplastic material

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

1. The colour of the paint shall be white or yellow (IS colour No. 356).

2. The cold applied paint material shall be homogeneously composed of binder, pigment, extenders and other additives as required for the formulation.

3. The pigments and extenders shall be uniformly dispersed in the binder medium dissolved in organic solvents.

4. The material shall be free from skin, dirt and foreign objects and shall comply with the requirements shown in table.(Ref: Table 800-11 of MoRTH Specifications)

Table: Properties of constituents of paint.

1. The specific requirements of reflectorizing glass beads are given in Clause 2810.3. than 400 micron and the minimum thickness of dry unbeaded coat of paint shall not be less than 200 micron.
2. The retro-reflective properties according to BS EN 1436:1998 shall be as given in table.(Ref: Clause 803.7.2 of MoRTH Specifications).

Table: Retro-reflective properties required s

6.4  Sampling and testing

1. The cold applied reflective paint shall be sampled and tested in accordance with appropriate ASTM/BS test methods.
2. Non-volatile matter in the paint determined as per ASTM D1644 shall be minimum 65% by weight.
3. The liquid paint shall have a density of 1.3 gm/cm3 when determined as per ASTM D1475.
4. Drying time of paint shall be 20 minutes maximum for a wet film thickness of 350 micron.
5. The paint shall not be applied when the surface temperature of the road is higher than 40°C.

1. f)The paint shall set to bear traffic after 40 minutes when the ambient temperature is higher than 24°C.

6. When tested according to ASTM D 968 using a sand abrasion tester, the quantity of sand required to remove 75 micron thick unbeaded dry film shall be more than 65 litres.
7. The unbeaded dry film shall pass the elongation test as per ASTM D 1737 and ASTM D 2205.
8. The unbeaded dry film shall pass the water resistance test as per ASTM D 1647 and ASTM D 2205.
1. The skid resistance of the beaded dry film shall not be less than 45 as per BS: 6044.
10. The Contractor shall furnish to the Engineer a copy of certified test methods from the manufacturer of cold applied reflective road marking paint showing the results of:

1. No pick up time as per ASTM D 711.
2. Resistance to wear as per ASTM D 4060 or as per ASTM D 968 from approved laboratories.
3. Material safety data sheet shall be obtained from the manufacturer.

7.  REFLECTIVE PAVEMENT MARKERS (ROAD STUDS) AND SOLAR POWERED ROAD MARKERS (SOLAR STUDS)

7.1 Reflective pavement markers (Road studs)

1. The plastic body of road stud shall be moulded from ASA (Acrylic styrene acrylonitrite) or HIPS (Hi-impact polystyrene) or acrylonitrile butadiene styrene (ABS) or any other suitable material approved by the Engineer.
2. The markers shall support a load of 13,635 kg tested in accordance with ASTM D 4280.
3. Reflective panels shall consist of number of lenses containing single or dual prismatic cubes capable of providing total internal reflection of the light entering the lens face.
4. Lenses shall be moulded of methyl methacrylate conforming to ASTM D 788 or equivalent.

7.2 Requirements

1. The slope or retro-reflecting surface shall preferably be 35±5° to base and the area of each retro-reflecting surface shall not be less than 13.0 cm2.
2. Each reflector or combination of reflectors on each face of the stud shall have a minimum coefficient of luminous intensity (CIL) shown in table.(Ref: Tables 800-13 & 14 of MoRTH Specifications).

7.3 Sampling and testing

1. The sampling and testing of the road studs shall be in accordance with appropriate ASTM/BS test methods.
2. The CIL is measured by the procedure given in ASTM E 809 or as per BS: 873 (Part 4).
3. The stud is considered as not failed, if the CIL measured at any position is less than the values given in table 2800-9 provided:

1. The value is not less than 80% of the minimum specified value and
2. The average of the left and right measurements for the specified angle is greater than the specified minimum.

7.4 Solar powered road markers (Solar studs)

1. The solar studs shall be made of Aluminium alloy and polycarbonate material which shall be absolutely weather resistant and strong enough to support a load of 13,635 kg tested in accordance with ASTM D 4280.
2. Solar studs may be white, red, yellow, green or blue or combination as directed by the Engineer.
3. The water resistance of solar studs shall meet the requirements of IP 65 in accordance with IS: 12063 category 2 for protection against water ingress.
4. The dimensions of solar studs shall not be less than 100 mm x 100 mm x 10 mm.
5. Solar studs shall have super bright LEDs so as to provide long visibility from a distance of more than 800 m. Its flashing rate shall not be less than 1 Hz.
6. The life of solar studs shall not be less than 3 years and shall be able to give the prescribed performance in the temperature range of -40°C to +55°C.

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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