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Supplemental Environmental Impact Statement (SEIS)

A public hearing to present and discuss a summary of the Draft Supplemental Environmental Impact Statement (Draft SEIS) was held at the Derry Municipal Center on September 22, 2009. All public comments received on the Draft SEIS were considered by NHDOT and FHWA and all revisions attributed to these comments were incorporated into the Final SEIS as appropriate.

The SEIS was finalized on May 3, 2010 and the FHWA Record of Decision (ROD) was released September 22, 2010. Completion of the SEIS process allows the DOT to continue to move forward with the I-93 Project.


In February of 2006 the CLF filed suit against the Federal Highway Administration (FHWA) and NHDOT seeking an injunction against the I-93 Improvement projects. During the court case, the CLF agreed not to block projects that would not necessitate the widening of the highway. These projects fell into two categories: repair/replacement of *red list bridges and construction of park and ride (PNR) facilities. Early action projects included in this preliminary agreement that have been completed to date are the Cross St Bridge Replacement (Salem), Exit 2 PNR (Salem), Exit 4 Bus Terminal, Exit 5 PNR (Londonderry), Exit 5 Bus Terminal and Bus Maintenance Facility and Reconstruction of a portion of Rte 28 (Londonderry). Another early action project to remove/reconstruct seven (7) red-listed bridges at Exit 1 was completed in November 2009.

The ruling was handed down in late August, 2007. Of the many counts included in the CLF suit, only one was found to have merit - that newer population projections should have been utilized in determining the project's impacts. As a result, the DOT was ordered by the Court to prepare a Supplemental Environmental Impact Statement (SEIS) to address the following:

  • How potential induced population growth could impact the effectiveness of the four-lane alternative as a traffic congestion reduction measure, and
  • How indirect effects of potential induced population growth could impact air quality and traffic on secondary roads.

Following the ruling, the Federal District Court approved an agreement allowing additional I-93 construction projects to move ahead. The construction work allowed by this agreement is focused on removing traffic from "red list" bridges in an effort to improve safety along the I-93 corridor. It includes two projects at Exit 3 in Windham and one at Exit 5 in Londonderry. The Windham projects include the Southbound Off-Ramp and Bridges over NH 111 and NH 111A, and Northbound Mainline reconstruction, awarded to The Middlesex Corporation and George R. Cairns & Sons, Inc. respectively. The project in Londonderry includes the reconstruction/reconfiguration of the southbound on- and off-ramps and the northbound on-ramp. This project was awarded to Severino Construction. Construction started in July 2008 and the project was completed in May 2010.

Supplemental Environmental Impact Study

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