rat run 
noun British informal
A minor, typically residential street used by drivers during peak periods to avoid congestion on main roads: our road was used as a rat run between two main roads...
- Sapling Road really has become a rat run since the bus lanes were introduced on St Helens Road.
- I live on a complete rat run between the High Road and Acton Lane.
- Householders in Moss Lane, Oswaldtwistle, had tried for years to stop traffic using the road as a rat run to the M65 motorway.