Code of Practice for Road Markings (Second Revision)
2015 Edition

IRC 35 advocates the use of Hot Applied Thermoplastic Compound as the preferred material for durable and highly reflective road markings, due to its quick drying properties, excellent endurance, and superior retroreflective qualities, typically lasting 2 to 3 years depending on traffic volumes. Solventborne and waterborne paints are generally reserved for temporary markings because they are less durable but easier to remove. Additional materials include cold applied plastics and preformed adhesive tapes, each suited for specific marking functions. Overall, thermoplastics are favored for their longevity and visibility.

Raised profile edge lines are continuous markings featuring regularly spaced ribs that provide both visual cues and tactile feedback, especially under wet conditions, as outlined in Clause 7.7.1. These ribs protrude above the water film to enhance visibility and generate vibrations when driven over. Typically, rib spacing should not exceed 500 mm, but expressways require closer intervals of 250 mm to maintain audible warnings. The width of these lines ranges from 150 mm to 200 mm, with rib heights between 4 mm and 8 mm, increasing to 11 mm on expressways. These markings should be absent at pedestrian and cyclist crossings to prevent hazards, thereby balancing safety for all road users.

No-overtaking zones on multi-lane roads are indicated by continuous solid lines where stopping sight distances are inadequate, particularly on vertical and horizontal curves, per Clauses 4.7.4 and 4.7.5. For four-lane dual carriageways, solid lane markings are applied in short sections to discourage overtaking in one-directional traffic flows. In six-lane or wider roads, the same approach is used with continuous markings where visibility is insufficient. On undivided highways with more than three lanes, a double solid center line marks the no-overtaking area, which must not be crossed. These zones are implemented when sight distances fall below the minimum visibility distances specified in Table 4.1.

Retro-reflectivity, measured as the coefficient of retro-reflected luminance (mcd/m²/lx), quantifies the amount of light reflected back to drivers from pavement markings. Dry retro-reflectivity initial and minimum values vary with design speed as per Table 15.1, measured using procedures outlined in Annexure E. Wet retro-reflectivity, reduced due to water films on glass beads, is also measured by Annexure E methods, with uniform initial and minimum standards regardless of speed: an initial value of 100 mcd/m²/lx and a minimum threshold of 50 mcd/m²/lx (Table 15.2). Maintaining these retroreflectivity standards ensures visibility under wet conditions, enhancing nighttime and adverse weather safety.

According to IRC 35, markings for bus bays include defined areas with passenger shelters and physical islands to facilitate safe boarding and alighting, supported by appropriate kerb loading markings (Clause 12.3). Bus stop markings should be accompanied by bus bay signage at the start of the transition approach (Clause 12.2.3), following IRC 70 and IRC 80 design standards for urban and rural stops respectively. Toll plazas require chevron markings and continuous lines on approaches to clearly delineate queue extents and guide traffic flow (Clause 12.5.3). While specific dimensional details are in the full standard, these provisions collectively ensure orderly operation and safety at these facilities.