The Collaborative International Dictionary of English v.0.48:
curbside \curbside\ n. the edge of a sidewalk that borders a curb; as, policemen stood at intervals along the curbside [WordNet 1.5]WordNet (r) 3.0 (2006):
curbside n 1: the side of a sidewalk that is bordered by a curb; "policemen stood at intervals along the curbside"