A highway number in India tells you who maintains the road, not how good it is

The numbering system is about jurisdiction

Indian roads are classified into national highways, state highways, major district roads and everything below, and the label indicates which authority is responsible for building and maintaining the road. It doesn’t, on its own, describe the surface, the width or the traffic.

National highways are numbered under a national scheme and carry a large share of long-distance freight. State highways connect within a state and are maintained by state agencies. Below that, district roads link towns to the network and vary from decent to appalling within a single district.

What follows is the point people get wrong. A well-maintained state highway can be a far better drive than a congested national highway through a string of towns, and a national highway number is no guarantee of anything except that somebody in Delhi is nominally responsible for it.

Divided or undivided is the variable that matters

The single most useful thing to know about a road is whether opposing traffic is physically separated. A divided carriageway with a median removes the head-on risk entirely and permits a steady average speed; an undivided two-lane road requires every overtake to use the oncoming lane.

On an undivided highway, average speed is set by the slowest vehicle you cannot get past, and overtaking against oncoming traffic is where the serious accidents happen. That is a structural feature of the road, not a matter of driver quality, and it is why journey times on two-lane highways are so much less predictable.

Expressways are the other end of the scale — access-controlled, divided, with no cross traffic and no roadside settlement. They are the fastest roads in the country by a wide margin, and they are also the ones where a breakdown leaves you somewhere with no services and no way to walk off.

A highway through a town stops being a highway

Much of the older national network runs straight through the middle of the settlements along it, and in those stretches the road is a market street with a highway number. Speed collapses, traffic mixes, and a fifteen-kilometre stretch can take as long as the sixty before it.

Bypasses have been built around many of these towns and are the reason travel times on some corridors have improved dramatically. Where the bypass exists, using it and stopping deliberately rather than crawling through is usually the better plan.

This is also why distance is such a poor predictor of time on Indian highways. The relevant question is how many towns the route passes through, not how many kilometres it covers, and a map that shows settlement density answers it better than a route summary does.

The carriageway is shared with things that are not cars

Indian highways carry trucks, buses, cars, two-wheelers, three-wheelers, tractors, bullock carts, cyclists, pedestrians and livestock, frequently on the same surface and sometimes in both directions regardless of which side they are on. Entry and exit happen anywhere there is a gap.

Trucks set the rhythm on the long corridors, and the overtaking behaviour around them is the main hazard. Slow-moving vehicles without lights after dark are a serious and well-known danger, which is the practical reason experienced drivers avoid night driving on undivided highways wherever possible.

Tolls are collected electronically on much of the national network now, which has removed a great deal of queuing at plazas. The arrangements and requirements change over time, so anyone driving their own vehicle should check the current system rather than assuming what applied on an earlier trip.

Choosing a route rather than accepting one

Navigation applications optimise for time using live data and they are generally good at it, but they will happily route a car through a narrow lane that technically connects, particularly in rural areas and hill country. A local driver overruling the application is usually right.

For a long drive, the useful preparation is to look at what kind of road each section is — expressway, four-lane divided, two-lane, district road — and to build the day around the slow sections rather than the average. The last hour of a journey on a district road can take as long as the first three on an expressway.

And plan the stops. Facilities along the network are wildly uneven, with well-equipped plazas on the newer corridors and long stretches with nothing dependable on the older ones. Fuel, a usable toilet and a place to rest aren’t distributed evenly, and it’s worth knowing where the gaps are before entering one.