Roundabout Design NH Route 28 and Route 171 Intersection

Client: NHDOT

Construction Cost: $2.2 Million

Key Facts:

  • Preliminary and Final Design
  • 2000FT of Roadway Construction
  • Accelerated timeframe for design and permitting
  • roundabout design improves roadway which has a history of fatal crashes

GM2 completed Preliminary and Final Design services, permitting support, as well as Right of Way (ROW) delineation and Registry Plan development for the NH Route 28 and NH Route 171 intersection in Ossipee. The scope of work involved the design of a single lane roundabout centered on the existing intersection along with approximately 1,600 feet of roadway reconstruction on NH Route 28 and approximately 400 feet on NH Route 171. In addition to the roadway design, GM2 coordinated with Carroll County to design waterline relocations for the existing facilities within the intersection. A closed drainage system along with a stormwater treatment swale were also incorporated into the project’s design. This project was identified for safety improvements by NHDOT due to history of severe and/or fatal crashes, most recently in the summer of 2018. Due to the safety concerns, the project schedule was accelerated in order for construction to begin in the summer of 2019, leaving 9 months to complete final design, ROW acquisitions and permitting.


ACEC Silver Award Recipient