access lane; service road; bypass
Refers to a road that runs alongside a main road, providing access to adjacent properties or serving as a bypass. Often used in the context of highways or freeways.
The service road alongside the expressway is used as a local access road by residents.
If you take this bypass, you can avoid the traffic jam.
Compound of 側 (side) and 路 (road, path). The exact historical derivation is uncertain, but the meaning is transparent from its components.