This document is the N-12 Relieves Congestion in Surprise Arizona Case Study. In Arizona, a new overpass and additional roads constructed in 7 months discussed.

To alleviate traffic congestion at Bell Road and Grand Avenue in Surprise, AZ, a new overpass and additional roads, lanes and ramps were built. The design-build project was given just seven months, between the end of baseball’s spring training and Thanksgiving, for completion.

Railroad tracks near Grand Avenue made realignment of Grand Avenue the best option. Initially, stormwater flow was going to be in a concrete-line open channel between the tracks and Grand Avenue. An alternative was to bury RCP. Instead, 54” (1,350 mm) N-12 was chosen for the twin runs of stormwater pipe. N-12 allowed flows adjacent to the tracks along with Grand Avenue flows to be combined. By running the pipe under

Grand Avenue, it allowed for height reduction of the overpass bridge and shorter ramps.

By using N-12 pipe, the total budget was reduced by 20 percent and the project was able to be completed in time because the N-12 pipe could be installed more quickly.

The installation was done in April-November 2016 using 6,500’ (1,981 m) of 54” (1,350 mm) N-12 pipe, 18”-30” (450-750 mm) and N-12 pipe Inserta Tee®.

Photographs of the project are included.