a road that is smaller than a main road, but is often connected to it 旁路,侧道,支线
Examples from the Corpus
side road• An escaperoute may be a back door, a side road or a lowwallfronting a garden.• I only know it was somewhere in a side road, where Highway i comes into Saigon.• The Jaguarslowed down and he pulled off the main highway into a side road.• He didn't see who was in the car and it went up a side road.