When people say that a road has "two lanes"?

  1. Two lanes total, one travelling in one direction, and one travelling in the opposite direction?

Two lanes total, one travelling in one direction, and one travelling in the opposite direction

  1. Two lanes travelling in one direction, and two more lanes travelling in the opposite direction?

enter image description here

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    In the US a "two-lane road" is one (single-vehicle-width) lane in each direction. (A "one-lane-road" is either a single one-way lane, or a single lane where vehicles must somehow take turns going opposite directions.) – Hot Licks Sep 1 '15 at 21:07
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    @HotLicks, a "one-lane road" can also refer to the "lane-and-a-half" dirt roads found in extremely rural area, where two vehicles can pass with care, but not at normal driving speed. – Mark Sep 1 '15 at 21:46
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    @Mark - Yes. Usually such a road includes true one-lane segments, but at intervals it's wide enough to allow two (relatively narrow) vehicles to pass each other. This kind of falls into the "somehow take turns" mechanism I mentioned. – Hot Licks Sep 1 '15 at 21:49
  • Around here, "two lane" refers to the former and the latter would be a "twin lane", though I'm not sure if this is a Canadianism or not. We also have the verb "twinning" for the process of turning the former into the latter. – Compro01 Sep 2 '15 at 7:56

Two-lane expressway (same concept as road) :

  • A two-lane expressway or two-lane freeway is an expressway or freeway with only one lane in each direction, and usually no median barrier.

Two-lane expressway: enter image description here

Two-lane road:

enter image description here


Your second picture represents a:

multilane road/highway:

  • (of roads and highways) having two or more lanes for traffic

enter image description here

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    Josh, I wouldn't call your top picture a typical "2-lane road" - it's an expressway. An expressway has entrance and exit ramps. The lanes are usually divided by a median barrier or grass barrier and an expressway has a generally higher speed limit. A 2-lane road is a road with one lane in each direction, divided by a double yellow line, intersected with other streets controlled either by 2-or 4-way stop signs and/or traffic lights. – Kristina Lopez Sep 1 '15 at 20:10
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    @KristinaLopez - I added a picture and descriptions, hope it is clearer now. – user66974 Sep 1 '15 at 20:16
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    Yeah, that completes it @Josh61! :-) – Kristina Lopez Sep 1 '15 at 20:50
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    I guess we just call it a side when forced to. But we generally just use the route name and then <direction>bound E.g., the accident on US60 westbound is also affecting eastbound traffic. Or a car travelling west on US 60 crossed the median into the eastbound lanes resulting in a head-on collision with a 18-wheeler. – Jim Sep 1 '15 at 21:43
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    @WS2--it spilled over into the northbound lanes. – Steven Littman Sep 1 '15 at 22:15

According to the World Road Association-PIARC, an international standards body, a two-lane road is simply a

Road designed to permit two lanes of traffic to be accommodated side by side.

A search on the term shows that this usage is used by governments and construction companies in the United States, Canada, New Zealand, and Scotland. We may presume that at least in industry circles, the understanding of a two-lane road would be something like what the Manual on Uniform Traffic Control Devices, which sets US national standards for road signs and markings, offers in this diagram:

US MUTCD diagram of two-lane roadways

Roads with more than two lanes, regardless of direction of traffic, are referred to generically as multi-lane roadways.

However, lanes should not be confused with carriageways or with directions of travel. Consider, for instance, this Wikimedia image of highway 401 in Ontario:

Traffic on the 401

There are sixteen to seventeen lanes of traffic, but these are divided up into six carriageways, three in each direction. So the confusion that a four-lane road refers to a road with four lanes in one direction may arise because it is hard to imagine such a large road on a single carriageway; almost certainly it would be at least a dual carriageway, with four lanes of traffic in each direction, but properly an eight-lane roadway.

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    To truly appreciate a 2-lane road, it helps to know a road that isn't. Here's one... (best bit from 3:00 to 5:50). youtube.com/watch?v=EHKCymOzDcY It actually works remarkably well, outside tourist season. Everybody else uses the passing places to allow overtaking, as well as passing in opposite directions. – Brian Drummond Sep 2 '15 at 18:55

A two lane road means one lane in each direction. Otherwise, there would be no need for special instructions, like this one, teaching drivers how to safely pass on a two lane road.


A two-lane road is the simplest road possible - no central dividing of the traffic, other than for a dotted line - just one 'lane' in each direction. But in Britain it is usually called a single-carriageway road.

In Britain this is a single-carriageway road:

It is also what I would call a two-lane road.

This is a two-lane dual carriageway

This is a four-lane motorway

with a northbound and a southbound carriageway.

The word carriageway (sometimes written as two separate words) long predates the internal combustion engine. It is defined as 'that part of a road which is open to vehicular traffic', in the early days this would have been horse-drawn. (OED).

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    Good except for “lane == carriageway” in US. A lane is a strip of “carriageway” which can only be occupied by a single vehicle at a time at any point along the roadway. A vehicle can ‘change lanes” by steering to cross the dotted white line into an adjacent lane. With a typical single-lane exit ramp a vehicle must be in the right lane to exit the freeway. – Jim Sep 1 '15 at 22:03
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    I'm just going to come right out and say it: American English does not have a word for "carriageway" (though the word "roadway" comes close.) The word "lane" means the same thing on both sides of the pond. – gatkin Sep 1 '15 at 22:19
  • Of course we talk about the northbound/southbound, or eastbound/westbound carriageway. But in the case of the M25 (the motorway which circles London) it is the clockwise/anti-clockwise carriageway. – WS2 Sep 2 '15 at 0:02
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    @gatkin Yes, I can see now that 'lane' means the same thing. But what do you say on those dreadful occasions (and they must happen anywhere) where some maniac finds his way on to the wrong carriageway? You must know the joke about the woman who phones her husband to urge him to be careful as police report that someone is driving up the wrong carriageway, and he responds with - 'there are scores of vehicles going the wrong way on my carriageway'. – WS2 Sep 2 '15 at 0:07
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    @WS2 "A two-lane road is the simplest road possible" - not true of course. Consider a single-lane one-way road. – Robin Elvin Sep 2 '15 at 9:57

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