I93 Exit 4a Project

Derry & Londonderry, New Hampshire

I-93 Exit 4A

Reducing congestion, improving safety, and promoting economic vitality for the towns of Derry & Londonderry, New Hampshire

The Towns of Derry and Londonderry (the Towns) and the New Hampshire Department of Transportation (NHDOT), in cooperation with the Federal Highway Administration (FHWA), are advancing an updated environmental study for the I-93 Exit 4A Project (Project). The Project consists of a new diamond interchange on I-93 in the Town of Londonderry, approximately one mile north of Exit 4. The new diamond interchange would provide access to the east side of I-93. A 1-mile connector roadway would be built on new alignment from the interchange to Folsom Road, near the intersection of North High Street and Madden Road, in the Town of Derry. Folsom Road, and subsequently Tsienneto Road, would be upgraded, and the intersections would be improved. In total, the Proposed Project corridor from I-93 to the intersection of Tsienneto Road and NH Route 102/Chester Road would be 3.2 miles. The purpose of the Project is to reduce congestion and improve safety along NH 102, from I-93 easterly through downtown Derry and to promote economic vitality in the Derry/Londonderry area.


Planning for the Project began in 1985, with a Draft Environmental Impact Statement (DEIS) being completed in 2007. A Public Hearing on the DEIS was held on September 12, 2007. In October 2015, the Governor's Office directed NHDOT to accelerate the Exit 4A Project, and the Project was subsequently incorporated in the state’s Ten Year Transportation Improvement Plan for 2017–2026. NHDOT and the Towns entered into an agreement under which NHDOT will provide administrative oversight to complete the environmental review process, then the Project will transition to NHDOT control during final design and construction.


Due to the amount of time that has elapsed since the 2007 DEIS, the FHWA has requested the preparation of updated studies that will be documented in a Supplemental Draft Environmental Impact Statement (SDEIS) in accordance with the National Environmental Policy Act (NEPA). These updated studies and documentation began in June 2016. The SDEIS will provide an up-to-date assessment of the environmental effects of the Project and the evaluation of reasonable alternatives that will consider updated information including  but not limited to, traffic, socioeconomic projections, land development proposals in the project area, and changes in environmental resources and regulatory requirements. After completion of the SDEIS and the presentation of a Preferred Alternative at a Public Hearing, a Proposed Action will be chosen with input from State and federal Agencies; State, Town and local officials; and the public. NHDOT and FHWA will complete the NEPA environmental review process by issuing a Combined Final EIS (FEIS) and Record of Decision (ROD).


Construction of the Project is anticipated to begin in 2019 and be completed by 2022. The programmed cost of the Project within the 2017–2026 Ten Year Plan is $56,855,000, including preliminary engineering, right-of-way, and construction costs.


What's New?


September 27, 2016 at 7pm

Derry Municipal Center,
14 Manning Street, 3rd Floor, Derry, NH


Meetings & Events



September 27, 2016 at 7pm

Derry Municipal Center,
14 Manning Street, 3rd Floor, Derry, NH


A combined Public Officials/Public Informational Meeting has been scheduled for Tuesday, September 27, 2016, to update the public on the Exit 4A interchange study in the Towns of Londonderry and Derry.


Click here for more information.


Status & Schedule

Technical studies are ongoing to update baseline information for the SDEIS. This work includes preliminary engineering updates; land use, traffic, and noise reports; water resources, wetlands, and wildlife technical studies; water quality monitoring reports; and an Interchange Modification Report. The steps in the environmental review process are:

Project History

In 1985, the Town of Derry first approached NHDOT regarding the possibility of obtaining funding for a new I-93 Exit 4A Interchange. The Southern NH Regional Planning Commission (SNHPC) conducted a transportation study for Derry later that year to evaluate alternatives to relieve traffic congestion along NH Route 102 in downtown Derry. Based on the results of this study, the Derry Town Council endorsed a new interchange alternative.

In 1987, NHDOT and the Towns began cooperating to develop an acceptable design for a new exit to I-93 between existing Exits 4 and 5 to serve both towns. The Towns were notified that the project was required to meet current NHDOT highway design standards. At this time the Towns initiated preliminary planning and engineering.

In 1988, an application for approval of a break in the limited access right-of-way for a new interchange on I-93 between existing Exits 4 and 5 was submitted to NHDOT and FHWA. This proposal received preliminary approval from FHWA in 1991, subject to several conditions, including compliance with the National Environmental Policy Act (NEPA). FHWA later determined that an EIS must be completed for the project. Additionally, only easterly access from the interchange was approved.

The formal EIS process began in early 1998. FHWA published a NOI to prepare an EIS, and a formal public scoping meeting was held. Twenty-two meetings were later held soliciting input from federal, state, and town officials and the public. The meeting groups included the Citizens Advisory Technical Committee (CATF) and Technical Advisory Committee (TAC), which included town representatives, regional and state planners and engineers, and the public. A major purpose of the early public involvement was to obtain input on identifying a reasonable range of alternatives to consider for the Project.

The EIS study paused in 2003 because of additional scope requirements identified through the interagency coordination process. In June 2005, the Towns re-commenced the EIS review process and previously collected data was updated.

In March 2006, at a meeting with federal, state, and town officials, a comprehensive summary was presented and discussed that compared the advantages and disadvantages of the alternatives. The Towns subsequently selected as their Preferred Alternative (Alternative A), a new Exit 4A Interchange located approximately 1 mile north of Exit 4. Concurrence in the selection of the Preferred Alternative was received from the resource agencies. In July 2007, FHWA approved the DEIS and issued it for review (FHWA-NH-EIS-07-01-D). The DEIS issuance was followed by a Joint NHDOT, New Hampshire Department of Environmental Services (NHDES) and U.S. Army Corps of Engineers (USACE) Public Hearing held on September 12, 2007 at the Derry Municipal Center. On March 3, 2008 a Necessity Meeting was held at the Derry Municipal Center to update the Special Committee members on comments received at the September 12, 2007 public hearing and to review the Towns’ responses. At the conclusion of that meeting, the Special Committee voted unanimously to approve the Necessity of the Project.


From March 2008 through December 2010, work progressed on addressing comments received on the DEIS, including developing compensatory mitigation for Project impacts on wetlands/waters of the United States. These efforts were initially limited to collecting one year of stream monitoring for chlorides (including Shields Brook) and performing a vernal pool field study in spring 2009. In late fall 2009, full time work resumed on the FEIS. These efforts were largely focused on updating the traffic data and the impacts associated with each alternative. In 2011, the environmental clearance for the project was put on hold because of funding issues.

In October 2015, the Governor’s Office directed NHDOT to accelerate the I-93 Exit 4A Project, and the Project was subsequently incorporated in the state’s Ten Year Transportation Improvement Plan for 2017–2026. NHDOT and the Towns entered into an agreement under which NHDOT will provide administrative oversight for the completion of the environmental review process, then the Project will transition to NHDOT control during final design and construction.

From December 2015 through February 2016, the consulting team identified the updates and additional technical studies necessary to complete the review of the project under NEPA and other environmental requirements through eight meetings of the EIS Review Team (EISRT). As part of these meetings, the EISRT performed a comprehensive reevaluation of the Project that considered changes in (1) environmental regulatory requirements, (2) existing conditions, (3) expected future conditions, and (4) the design of the Project. In addition to the consulting team, the EISRT consisted of representation from the Towns, FHWA, and NHDOT.

Based on the updated technical studies identified by the EISRT, the Towns entered into a contract with the CLD Consulting Engineers team to prepare the remaining environmental documentation required for FHWA approval (an SDEIS and FEIS/ROD). Work on the SDEIS commenced in June 2016.



What is the purpose of this Project?

The purpose of the I-93 Exit 4-A Project is to reduce congestion and improve safety along NH 102, from I-93 easterly through downtown Derry and to promote economic vitality in the Derry/Londonderry area. Because current traffic congestion along NH 102 affects the vitality of local businesses and community character, the Project will be designed to alleviate peak period congestion along NH Route 102 through downtown Derry by separating through-traffic on NH 102 headed for the Interstate system from local, destination-oriented traffic. The Project will also be designed to improve interstate accessto the east of I-93 for commercial and industrially zoned lands in both Derry and Londonderry. This coordination will allow for their planned and orderly development and will promote economic growth in the Derry and Londonderry area.

Who is involved?

Because this Project extends over multiple jurisdictions and intersects with the Interstate system, a collaborative approach is critical on this project. The New Hampshire Department of Transportation (NHDOT) is therefore working in partnership with the Federal Highway Administration (FHWA) and closely with the consultant team led by CLD Consulting Engineers, Inc., as well as the public and representatives from an Environmental Impact Statement Review Team (EISRT). The EISRT includes representatives from NHDOT, FHWA, Londonderry, Derry, and the consultant team. NHDOT is also working with other cooperating agencies including the U.S. Army Corps of Engineers (USACE), U.S. Environmental Protection Agency (USEPA), New Hampshire Division of Historical Resources (NHDHR), and the New Hampshire Department of Environmental Services (NHDES). Cooperating and participating agencies for the SDEIS will confirmed and a Coordination Plan prepared pursuant to FHWA's 23 USC 139 environmental review process (as amended by the FAST Act in 2015). The Coordination Plan will identify the roles and responsibilities for each agency and will include a detailed project schedule.

What is an environmental impact statement (EIS)?

The National Environmental Protection Act (NEPA) “requires Federal agencies to prepare environmental impact statements (EISs) for major Federal actions that significantly affect the quality of the human environment. An EIS is a full disclosure document that details the process through which a transportation project was developed, includes consideration of a range of reasonable alternatives, analyzes the potential impacts resulting from the alternatives, and demonstrates compliance with other applicable environmental laws and executive orders. The EIS process is completed in the following ordered steps: Notice of Intent (NOI), draft EIS, final EIS, and Record of Decision (ROD).” Consistent with the FAST Act, a single document combining the FEIS and ROD will be utilized unless certain conditions are met (substantial changes in the action, or significant new information/circumstances relevant to environmental concerns).

What is a supplemental Draft EIS?

A supplemental EIS is required under NEPA when changes in the proposed action or new circumstances would result in significant environmental impacts not evaluated in the previous DEIS or FEIS (23 Code of Federal Regulations [CFR] 771.13). The purpose of this SDEIS is to provide an up-to-date assessment of the I-93 Exit 4A Project that considers changes in the design of the alternatives (through updated preliminary engineering studies), changes in the existing environment, changes in environmental regulations, and other “significant new circumstances or information relevant to environmental concerns have a bearing on the proposed action or its impacts” (40 CFR 1502.9 (c)(1)). New circumstances affecting the Project include, but are not limited to: the final design for the widening of the I-93 mainline in the Project area, approved developer plans for new mixed-use development on both the east and west sides of I-93 (Woodmont Commons), the chloride total maximum daily load (TMDL) for the Beaver Brook watershed, and updated demographic projections affecting future travel demand, among other changes.

Pursuant to Council on Environmental Quality (CEQ) and FHWA regulations, the SDEIS is subject to the same distribution and public review requirements as the previously published DEIS, except that scoping is not required (23 CFR 771.130(d)).

How can I stay informed and participate?

It is important to get public feedback on this project so that the concerns and needs of the community can be accurately incorporated into the project design. You are encouraged to stay involved by:

  • Exploring this website for more information on the project.
  • Signing up for future project notices. You can sign up through the “Feedback” section of this website. In the Subject section of the Feedback page, select: “Please add me to the mailing list” from the drop-down menu.

What consultants are supporting the project?

  • CLD Consulting Engineers, Inc.
  • Louis Berger U.S.
  • Normandeau Associates, Inc.
  • RKG Associates, Inc.
  • Southern New Hampshire Planning Commission (SNHPC)
  • Victoria Bunker, Inc.
  • Preservation Company



NHDOT Project Manager

Keith Cota, P.E.

New Hampshire DOT

John O. Morton Building

P.O. Box 483

Hazen Drive

Concord, NH 03302-0483

Phone: (603) 271-1615



Consultant Project Manager

Christopher Bean, P.E.

CLD Consulting Engineers, Inc.

540 Commercial Street

Manchester, NH 03101

Phone: (603) 668-8223 x102




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© 2017 NH Department of Transportation | Last updated: 10-January-2017