carriageway

from WordNet (r) 3.0 (2006)

carriageway
    n 1: one of the two sides of a motorway where traffic travels in
         one direction only usually in two or three lanes

from The Collaborative International Dictionary of English v.0.48

carriageway \carriageway\ n.
   one of the two sides of a motorway where traffic travels in
   one direction only, usually in two or three lanes. [British]
   [WordNet 1.5]