service road

noun2

1. •
   A relatively narrow road which runs alongside a major transportation route, such as a canal, a railway line, or a controlled-access highway.

   • [I]t can only pinpoint phones to within a few hundred feet. That makes it difficult to tell if a signal is coming from a vehicle on the highway or from one on a parallel service road. — 2006
2. •
   A route which enters or circulates through an institution, compound, land area, etc. for purposes of private access, maintenance, or security.

   • From the day-use area behind Longmire Lodge, we walked up the service road behind the ranger station and employee housing. — 2004