I always saw a distinction between the two, but perhaps that's not
correct. I have always thought of "roadway" as referring to the entire
width of the system from curb to curb including shoulders. Carriageway
then would be a component of the roadway, not coextensive with it.
I would define carriageway as contiguous traveled way. Divided highways
would have two carriageways comprising the traveled way. To me, the
roadway includes both traveled way and median, where the median is not
excessively wide (i.e. concrete or narrow grass).
MIT - B.S. '05, M.S. (Transportation) '06
"Roadway" is the commonly used term in the U.S. for a directional set of
lanes, and is the term used in the 4 state DOTs that I am personally
I thought that "carriageway" was an English term for "roadway".
I just checked the dictionary (as past discussions support, not the
best place to look initially for roadgeek term definitions), and I
guess it could apply to both.
http://www.m-w.com/dictionary/roadway , 1a, says
"the strip of land over which a road passes".
However, the same entry, 1b, specifies "roadbed";
http://www.m-w.com/dictionary/roadbed , 2b, says
"the part of the surface of a road traveled by vehicles".
Note the last three words. :)
(I chose Merriam-Webster because I was taught that it's the closest
thing that there is to "official" American English.)
But isn't the roadbed what lies BENEATH the asphalt?
> But isn't the roadbed what lies BENEATH the asphalt?
Yeah: "roadbed", 2a:
"the earth foundation of a road prepared for surfacing"
Ambiguous, ain't it :p
> I have noticed that American posters frequently use the term
> "carriageway" to describe one of the two strips of pavement (and
> associated adjacent components) of a divided highway.
I generally use 'carriageway' only when talking about roads outside
North and South America. I use 'interlane' as a synonym for North and
South America. I consider both terms to refer both to the traveled way
and improved shoulders where they are provided.
> Is "carriageway"
> becoming a term used in official circles in the U.S., like "roundabout"
> has, or is it just the preference of the posters? (For the record, I
> prefer "roadway" since it's easier to say and to type :) )
I think 'carriageway' is becoming popular among M.T.R. regulars (not
road agencies, as far as I can see) because it is a convenient way of
referring to one half of a divided highway. 'Interlane' used to have a
similar function but I have to admit I am reviving it, because the most
recent usage I have seen of it (other than my own postings) is an
article C.H. Purcell wrote on the Bayshore Freeway in the mid-1940's.
I do not like to say 'roadway' when referring to just one half of a
divided highway since, unless it is appropriately qualified, I consider
it to refer to every part of such a facility which is open to vehicle
travel. I think most state D.O.T.s get around this problem by making
sure to specify a direction when they mean just one interlane (e.g.,
"westbound lanes," "westbound roadway").
As others have noted, "carriageway" is used as a synonym for "roadway"
in Britain, EXCEPT that, unless it is appropriately qualified, it is
always considered to refer just to one half of a dual carriageway.
Occasionally, when it is used in contradistinction to "hard shoulder,"
its meaning can be restricted to just the traveled way (e.g., "he
stopped in the carriageway instead of on the hard shoulder"). (B.T.W.,
"hard shoulders" are always "hard" whether they are paved or not. The
hard shoulders on the original M1 were stabilized vegetated = grass.)
P.S. As I understand it (I don't have the reference but I think it
must have come from one of Bill Bryson's books on the English
language), the term 'roundabout' was invented in the mid-1920's by an
American working for the B.B.C. Another proposed traffic term,
"stop-and-goes" for "traffic signals," didn't make it. Nowadays the
use of the word 'roundabout' in the U.S.A. as an alternative to
'traffic circle' has absolutely nothing to do with Anglophilia. It has
everything to do with the fact that the key design principle (yield on
entry) was developed in Britain, and highway agencies' need to
establish a clear distinction between modern roundabouts they want to
put in and the less safe older (and less safe) rotaries or traffic
circles which were based on weaving or entering traffic having priority.
> I do not like to say 'roadway' when referring to just one half of a
> divided highway since, unless it is appropriately qualified, I consider
> it to refer to every part of such a facility which is open to vehicle
> travel. I think most state D.O.T.s get around this problem by making
> sure to specify a direction when they mean just one interlane (e.g.,
> "westbound lanes," "westbound roadway").
The (American) press seems to do this frequently, although often with
the singular "lane", so you get something like "the right lane of the