This document is the case study for Beyond the Highway, Salem, NH. DOT widened 1.3 miles of N I-93 and 1.8 miles of S I-93 to create 3 lanes in each direction.

To reduce congestions and improve safety from Salem to Manchester, the New Hampshire DOT widened and reconstructed a 1.3-mile (2 km) northbound stretch of I-93 and a 1.8-mile (2.9 km) southbound run at I-93’s Exit 2. The reconstruction created three lanes in each direction.

Water quality permits for the reconstruction require strict standards for stormwater treatment with no net increase in total suspended solids (TSS), phosphorous or nitrogen. Stormwater collection systems will gather runoff and convey the stormwater runoff to treatment areas to protect the area’s numerous creeks, ponds, brooks and lakes.

Over 190,000’ (58,000 m) of N-12 pipe was chosen for the project. N-12 was the product of choice based on structural and durability performance, competitive costs and the ability to withstand the soil’s corrosive nature. Being able to provide corrosion and chemical resistance, means N-12 gives a long-term advantage over other materials

The installation was done in October 2015 using 190,360’ (58,021 m) of 6”-36” (150-900 mm) N-12®.

Photographs of the project are included.