Skip to Content

“Two-lane Road” — Here’s What It Really Means

“Two-lane Road” — Here’s What It Really Means

Sharing is caring!

On the face of it, this seems like a straightforward question. 

In many ways, it is. However, there still seems to be much discussion about what is and isn’t, technically speaking a two-lane road. 

So, without further ado, let’s dive right in. 


What is a two-lane road? 

A two-lane road is a road with two lanes, with one single-vehicle-width lane going in either direction and no median barrier between the lanes. In the United Kingdom, it is usually referred to as a single carriageway. 

A single-carriageway should not be confused with a single-track road with just one lane. Single-track roads have places for cars to pass one another in opposite directions. 

Many people also call a “single carriageway” an “undivided highway” because it lacks a median barrier between the lanes.

It is important to distinguish between lanes of traffic and carriageways, considering the confusion that seems to arise between the UK and the US on this point. 

A two-lane road has two lanes but only one lane for each direction of traffic. 

A two-lane road usually has at least segments where passing is permitted, as indicated by a broken yellow centerline. It may also have zones where no passing is permitted, as solid or double-solid yellow centerlines indicate. 

The fact that a two-lane road has sidewalks or road verges, such as exit and entrance ramps, does not prevent it from being a two-lane road. 

The dimensions and designs of roads have a rich history. The term “carriageway” long predates cars. 

It was derived in the 12th century, when the Laws of Henry I, which were given out between 1114 and 1118, proscribed the minimum width for the via Regia (the King’s Road).

Henry I of England mandated that roads be wide enough for two carriages to pass one another. 

In addition, he also said they had to be wide enough for 16 armed knights to ride beside one another, but that is a story for another time. 

Unlike a two-lane road, a double carriageway has not one but two lanes going in either direction, which are divided by a central reservation, usually a strip of grass, often with metal barriers and vegetation. 

A multi-lane road or highway has two or more lanes for traffic in either direction. A multi-lane road can have as many as 26 lanes, as the Katy Freeway in Houston, Texas does.