WordNet (r) 3.0 (2006):

expressway
    n 1: a broad highway designed for high-speed traffic [syn:
         expressway, freeway, motorway, pike, state
         highway, superhighway, throughway, thruway]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "expressway":
   Autobahn, US highway, alley, alleyway, arterial, arterial highway,
   arterial street, artery, autoroute, autostrada, avenue,
   belt highway, blind alley, boulevard, bypass, byway, camino real,
   carriageway, causeway, causey, chaussee, circumferential, close,
   corduroy road, county road, court, crescent, cul-de-sac,
   dead-end street, dike, dirt road, drive, driveway, freeway,
   gravel road, highroad, highway, highways and byways,
   interstate highway, lane, local road, main drag, main road, mews,
   motorway, parkway, pave, paved road, pike, place, plank road,
   primary highway, private road, right-of-way, ring road, road,
   roadbed, roadway, route nationale, row, royal road, secondary road,
   speedway, state highway, street, superhighway, terrace,
   thoroughfare, through street, thruway, toll road, township road,
   turnpike, wynd