“I was driving down a two-lane road, when suddenly <something interesting happened>”
What kind of road does the term “two-lane road” suggest to you? Is it a road with two lanes in each direction, or a road with two lanes total (one lane in each direction)?
Two lanes total.
One lane in each direction. I’d call a road with two lanes in each direction a “four lane road.”
A “two lane road” is like a country highway-- one lane in each direction. A “two lane freeway” has two lanes in each direction. A “two lane highway” is vague.
Wikipedia says a two-lane expressway has two lanes total (1 in each direction). The article also uses the term “two-lane freeway” in the same meaning.
Two lanes total. Please see the documentary on the subject: “Two Lane Blacktop.” 
Two lane roads are all too common here. Most highways in my part of the state are 2 lane roads built 50 or more years ago. We have two major Interstates but they are in the Northern/Central part of the State.
Clearly, this is yet another example of Wikipedia’s horrific accuracy. A source not to be trusted.
I live just off a two-lane highway, one each way – it’s 80 miles to the closest actual freeway.
Here in the UK I would call a road with one lane in each direction just a road or lane.
Confusingly when you see a road sign here saying ‘duel carriageway ahead’ that means two in each direction or four lanes in total.
Just come back from a holiday in the far north of Scotland where many of the roads are just one lane with passing spaces. The road signs warning of them ahead stated ‘single track road ahead’ - so maybe a carriageway and a track differ in some technical way?
http://en.wikipedia.org/wiki/Single-track_road#Single-track_roads_in_Scotland
I suspect US versus British usages will differ, as in so many things.
I think “dual carriageway” just means that there are two separate strips of tarmac with some kind of division between them, i.e. what North Americans would call a divided highway. True, in the UK each side usually has two lanes, but there are examples of three lanes each side, and a few places where there’s just one lane each side.
Anyway, to me “two-lane road” is ambiguous. I remember when I was a kid being amazed that they had eight-lane freeways in America. Then I realised it meant eight lanes in total, not both ways (although who knows, maybe there are a few examples of that).
Not at all. It’s a road, and you know what that is, right? Does it tell how many lanes on the road? Yes, there are two. It doesn’t say “on one side of the road.” Does it tell anything about direction of travel allowed? No, it could be a one-way or two-way road. It’s ambiguous only as to the use of the road or the allowable travel direction. It’s not ambiguous as to the number of lanes. If there are more than 2 in any direction, it is not a 2-lane road.
The most common use of a road with 2 lanes is one in each direction, but that’s not required to be a 2-lane road. A 2-lane road does not have 3,4, or more lanes because it’s a 2-lane road. If it had 4 lanes in any direction or any combination of directions, it would be a 4-lane road.
Highway 401 through Toronto has as many as 18 lanes in total–9 in each direction. Though the main travel lanes are fewer; some of them are transfer lanes between collector and express.
If I got on a duel carriageway I’d expect to see steampunkers jostling each other from the top of horse-drawn carriages and attacking each other with ornate pistols.
Sorry Musicat, but that is just your opinion. It is misleading or at least open to interpretation. The standard road is one lane each way, if somebody is bothering to make the distinction to me that is is a two lane road I would probably equate it with what I would call a duel carriageway (although strictly speaking that only denotes how many lanes there are going in my direction - unless the other carriageway was also a duel carriageway.
Essentially, to me, the “two lane” part sounds redundant if it just means one in either direction so it must mean something else. But as I said previously, part of this could just be a UK v US thing.
What on earth is a “steampunker”? I don’t think we have them in the UK let alone let them on our dual carriageways. 
You should have said “m’kay” rather than “right”. That way, it would have been even more patronising. Anyway, that this thread exists at all, and that so far about 10% of respondents have voted for “four lanes in total”, suggests that there is in fact some ambiguity.
There is a 7 or 8 lane highway (so 14-16 lanes total) in Dubai.
I have a related question. In the UK, where cars are right-hand drive and you drive on the left side of the road, if there’s two lanes traveling in the same direction, do you pass slower-moving vehicles using the right-most of the two lanes?
Yes. Same system - fastest lanes in each direction are nearest to each other.
I have indeed seen a one-way, two-lane road. Even if most two-lane roads are what one would normally consider a standard road, some deviation from the one-each-way can happen.