National Highway Chainage and Kilometre Stones in India: A Practical Guide

Evergreen explainer: This guide explains established highway location terminology. It is not an announcement of a new road opening, toll change or current traffic condition.

National highway project documents often identify a bridge, junction, work zone or proposed utility crossing by a kilometre reference rather than a familiar town name. Road users, meanwhile, encounter kilometre stones and destination signs. These systems are related but not always interchangeable. Understanding the distinction helps readers interpret official documents and communicate a location more precisely.

What is highway chainage?

Chainage is a distance measured along an identified road alignment from a specified reference origin. Engineers use it to locate a point on a project. For example, Km 12+450 conventionally means 12 kilometres and 450 metres from the relevant project origin. It is a location reference, not a speed limit or a promise of remaining journey distance.

Always check which alignment and origin the document uses. A contract may distinguish existing chainage from design chainage, especially where a new alignment or bypass differs from the old road. An NHAI technical schedule for a Dwarka Expressway package, for example, separately labels existing and design chainage and identifies the design range as Km 5+300 to 9+500. That is a historical document example, not a current construction-status statement.

How is a kilometre stone different?

A roadside kilometre stone is a physical distance marker intended to help road users orient themselves. It may display distances to places along the route. A chainage value in a tender, by contrast, identifies a position within a defined engineering reference system. Do not assume that a project document’s Km 12+450 necessarily corresponds to a roadside marker labelled 12 km.

MoRTH’s historical instructions address how kilometre stones are installed, how reference points for towns are selected, and how bypasses affect distance marking. The ministry has also issued instructions for the upkeep of damaged, missing or defaced kilometre stones and road signs. Such instructions explain the purpose of the system; they do not establish that every marker on every highway is currently accurate.

Reading common highway references

• Km 0+000: the defined zero point for that alignment or package.
• Km 7+250: a point 7.25 km along the specified alignment from its origin.
• Km 21+800 to Km 24+100: a 2.3 km chainage interval, assuming the same reference alignment.
• LHS/RHS: left-hand or right-hand side in the reference direction specified by the project; do not infer the side without that direction.
• Existing/design chainage: different reference systems that may require a conversion table.

Why a bypass can change the reference

Suppose an older highway travels through a town while a new bypass takes a different route. The physical distance between junctions can change, and project engineers may measure the new alignment independently. Historic MoRTH guidance specifically discusses kilometre stones on bypasses and signs directing drivers towards the town or along the bypass. Therefore, comparing two chainage figures without checking their reference system can lead to the wrong location.

How to describe a road problem accurately

When reporting a pothole, damaged sign or obstruction, note the national highway number, direction of travel, nearest named interchange or village, visible kilometre marker, and a safe GPS location if available. Mention the carriageway side and nearby landmarks. Do not stop in a live traffic lane merely to read or photograph a marker. For guidance on checking disruptions, see how to check highway closures and diversions.

Before a long journey, consult the national highway project status guide to understand why an approved or under-construction section should not be assumed open. For NH identification, see how national highways are numbered. If you need the correct toll for a route, use the separate toll charge verification guide.

Common mistakes to avoid

• Using a project chainage as a destination-distance estimate without checking the origin.
• Assuming old and new alignments have identical kilometre references.
• Confusing a route number such as NH 48 with a chainage value.
• Assuming an old tender document proves a project is open today.
• Relying on a single damaged or missing roadside marker when reporting an emergency.

Frequently asked questions

Does Km 10+500 mean 10.5 km?

Yes, within the relevant chainage system it denotes a position 10 kilometres and 500 metres from the defined zero point.

Can two documents show different chainage for the same place?

Yes. Existing-road and design-road alignments, different package origins and later revisions can produce different references. Compare the alignment drawings and chainage conversion schedules.

Is chainage the same as the distance remaining to a city?

No. Chainage measures position along a defined alignment; a destination sign normally communicates distance to a named place.

Official reference documents

• MoRTH compendium: kilometre stone installation and bypass reference guidance (historical circulars).
• MoRTH circular dated 14 June 2002: upkeep of road signs and kilometre stones.
• NHAI technical schedule: existing and design chainage example.

Editorial note: Source documents explain terminology and historical standards; they should not be treated as real-time highway condition reports.