IRC Code 79: Step-by-Step Guide to Installing Road Delineators - The Role of Median Markers in Road Safety

Road delineators are one of the most effective visual aids used to enhance road safety and reduce accidents, especially in conditions of low visibility such as night driving or adverse weather. Recognizing their importance, the Indian Roads Congress has developed IRC Code 79, formally titled IRC:79-2019 Recommended Practice for Road Delineators. This standard provides comprehensive guidelines for the design, installation, and maintenance of various types of road delineators, including median markers, which play a crucial role in improving road safety.

This detailed blog presents a step-by-step guide to installing road delineators as per IRC Code 79 and explains how median markers contribute to safer roadways.

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What is IRC Code 79?
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IRC Code 79 defines national standards for the use of road delineators in India. These include four types of delineators:

1. Roadway Indicators
2. Median Markers
3. Hazard Markers
4. Object Markers

Each type of delineator serves a unique purpose. Roadway indicators guide drivers along the alignment of the road. Median markers improve visibility of medians and prevent collisions with them. Hazard markers indicate the presence of hazards such as guardrails and abutments. Object markers highlight obstacles within the vehicle flow path, such as roundabouts or structures within the right-of-way.

Importance of Road Delineators in Road Safety
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Road delineators provide essential guidance to drivers by clearly outlining the edges and alignment of the roadway. They are particularly valuable in poor visibility conditions, on complex road alignments, and at night. Their use can reduce the risk of accidents caused by driver confusion, lane departure, or collision with roadside objects.

Median markers specifically enhance the visibility of medians at night and during adverse weather, preventing vehicles from unintentionally colliding with the median and helping maintain safe lane discipline.

Step-by-Step Guide to Installing Road Delineators (As per IRC Code 79)
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Step 1: Planning and Selection

The first step involves analyzing the road section to determine the appropriate type of delineator required. Factors to consider include the presence of curves, gradients, straight sections, medians, nearby hazards, and structures. Based on this analysis, the suitable delineator type should be selected. Median markers are selected for central medians on divided roads, while roadway indicators are used along road edges, and hazard markers are installed near obstructions.

Step 2: Preparing the Installation Site

Before installation, the site must be prepared. For median markers, the surface of the concrete or solid median must be cleaned and made smooth. For roadway indicators, a proper foundation made of M-25 grade concrete is required to ensure stable installation. It is important to ensure that the installation surface is level and clean.

Step 3: Installing Median Markers

According to IRC Code 79, Flexible Median Markers (FMM) must meet specific design and performance requirements. They are made from tough, injection-molded, flexible thermoplastic material. The body of the marker is black, and the retro-reflective surface is fluorescent yellow, using Type XI reflective sheeting.

The minimum height of the marker must be 180 mm, with a minimum width of 120 mm. The reflective area should be no less than 90 square centimeters. The marker should be designed to withstand 750 impacts and a tensile load of 50 kilograms-force, ensuring durability.

Installation involves applying epoxy adhesive to the prepared surface of the median. The marker is then anchored using drilling and grouting methods to secure it in place. During installation, it is essential to position the marker correctly so that its reflective face is perpendicular to the direction of travel, providing maximum visibility to oncoming drivers.

For spacing, median markers should be installed every 2 meters in urban areas and every 5 meters on highways and expressways, unless otherwise directed by the supervising engineer.

Step 4: Installing Other Types of Delineators

Roadway indicators are typically installed at a height of 800 to 900 millimeters above the ground. On straight sections of road, they should be spaced 50 to 70 meters apart. On curves, the spacing is adjusted according to the curve radius, as detailed in the code.

Hazard markers are installed near obstacles such as bridge abutments or guardrails. These markers consist of alternating black and yellow stripes sloping downward at a 45-degree angle. They should be placed just ahead of the obstruction and at a height that ensures visibility to drivers.

Object markers are used to indicate obstacles within the vehicle path, such as traffic islands, toll booths, and tunnel entrances. They should be installed in a position that provides full visibility to approaching traffic.

Step 5: Orientation and Positioning

For all delineators, it is crucial to ensure that the retro-reflective surface is oriented perpendicular to the direction of traffic flow. This positioning maximizes visibility, especially at night or in adverse weather conditions. Median markers should be aligned properly on the median to provide consistent visual guidance to drivers.

Step 6: Maintenance of Road Delineators

Proper maintenance is essential to ensure that delineators continue to provide effective visual guidance. Delineators should be periodically cleaned, especially after rainfall, to remove dirt and debris that can reduce reflectivity. The reflective sheeting used must comply with IRC:67 warranty requirements, and any damaged or faded markers should be replaced promptly.

It is also important to maintain the area surrounding the delineators. Grass and bushes should be trimmed regularly to prevent them from obstructing the view of the delineators.

The Role of Median Markers in Road Safety
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Median markers are particularly effective in preventing side-swipe and head-on collisions by improving the visibility of medians. They help drivers maintain lane discipline and avoid accidental impact with the central divider, especially on poorly lit roads or during adverse weather.

Median markers also contribute to driver confidence by providing clear, continuous guidance, particularly on high-speed roads, expressways, and urban divided roads. Their flexible, reboundable design ensures that they remain functional even after repeated impacts.

By implementing median markers as specified in IRC Code 79, road agencies can significantly enhance the safety of the road network and reduce accident rates.

Conclusion
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Implementing road delineators in accordance with IRC Code 79 is an essential part of modern road design and safety management. These delineators provide critical guidance to drivers, reduce accident risks, and enhance the overall driving experience.

Median markers, in particular, play a vital role in improving the visibility of central medians and preventing collisions. By following the step-by-step installation guidelines provided in IRC Code 79, road authorities, planners, and contractors can ensure that these safety devices are installed correctly and maintained effectively.

As India continues to expand and modernize its road network, adherence to IRC Code 79 will remain a key factor in achieving safer and more efficient transportation systems.

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