With the coming completion of the first part of an extensive New Hampshire Department of Transportation (NHDOT) corridor improvement project, the towns of Derry and Londonderry are one step closer to achieving goals of improved traffic flow, increased traffic safety, and expanded economic opportunities.

The multi-phased Interstate 93 Exit 4A Project, for which planning began in the 1980s, is seen as a critical step in expanding economic vitality in Derry and Londonderry by opening additional land adjacent to the highway for development. The project also aims to reduce congestion on New Hampshire Route 102 between the two towns, relieve traffic on secondary and residential roads, and improve traffic capability on Folsom Road, which leads to the heart of Derry's business district.

The existing Exit 4 is congested through the heart of Derry, said NHDOT Civil Engineer Tyler Reisdorf from the project's Field Support Team. “The area is so developed that road expansion or improvement is not practical,” he said. “The route is used a lot for traffic from Boston and other points to the south, including many commuters and heavy truck traffic.”

The Exit 4A project will construct a new interchange on I-93 in Londonderry, about a mile north of Exit 4. Included is the construction of a new road, named Old Rum Trail, between the interchange in Londonderry and Folsom Road in Derry. The project corridor continues easterly with upgrades to Folsom Road, Tsienneto Road, and NH Route 102 (Chester Road). Work on I-93 is approximately 1 mile long.

Folsom Road in Derry will be widened to two lanes each way and connect to Old Rum Trail in order to pull more traffic from NH Route 102. To meet stormwater permitting requirements, stormwater treatment infrastructure will be added throughout the project corridor.

The first project — one of three major construction phases of five overall construction projects which comprise the Exit 4A project — is designated as the 13065A Project.

“The Derry-Londonderry 13065A Project is part of the overall I-93 Exit 4A interchange construction in Londonderry, located approximately 1.25 miles north of Exit 4 and 2.25 miles south of Exit 5,” said Richard Arcand, NHDOT Public Information Officer. “This work includes a connector road — Old Rum Trail — on a new location that leads easterly from the new interchange for approximately 0.75 miles, where it will tie into the existing street system in Derry.

“Overall, approximately 2.25 miles of Folsom Road and Tsienneto Road will be improved, ending at the Tsienneto Road intersection with NH Route 102. Approximately 2,000 feet of NH Route 102 will be improved near the Tsienneto Road intersection.”

Weaver Brothers Construction Company of Bow, New Hampshire, is the primary contractor on the 13065A Project and is in the process of being awarded the contract for 13065B. For 13065A, Vanasse Hangen Brustlin (VHB) was the designer. For 13065B, the designers are McFarland Johnson for the roadway and VHB for the structures and signals. The bridge contractor for 13065A is Beck and Belucci, Inc.

Subcontractors for the 13065A Project include: Continental Paving, Inc.; H.B. Flemming; AJ Camerons Sod Farms; Capital Well Co.; HS&G Erosion Control; JCB Colby, Inc.; John Brown and Sons; Headwater Consulting; Maine Drilling and Blasting; Markings, Inc.; NH Rock Reduction; TF Moran, Inc.; Tri State Curb, Inc.; Underground Testing and Services; and DeLucca Fence Company.

The Interstate 93 Exit 4A Project is federally funded. According to Reisdorf, construction funding for the three construction projects is as follows: 13065A, approximately $45 million; 13065B, approximately $31 million; and 13065C’s construction cost is not yet determined. The 13065C Project is currently expected to be less than the first two projects because it will not be as complex.

“The 13065A contract was bid in May 2022,” said Adam Bates, Weaver Bros. Construction Co. Owner. “The official groundbreaking of the project was August 2, 2022, and construction began that same month. The second phase [13065B] is expected to be completed in June 2028, at which time the new exit will be opened to traffic.”

“The Exit 4A project consists of five separate construction contracts,” Reisdorf said. “Two contracts were for demolition and have been completed.”

The 13065A Project included construction of the new Exit 4A on- and off-ramps with noise abatement barriers; a new two-span metalized steel girder bridge over Interstate 93, with high performance steel flanges over the pier and a composite concrete deck; approximately 4,000 linear feet of connector roadway east toward Derry; relocation of the Wheeler Pond Tributary; ITS infrastructure, overhead sign structure additions and adjustments, and building/structure demolitions; and construction of water quality stormwater treatment areas.

Proposed work for the 13065B Project includes the construction of Old Rum Trail, Folsom Road, Tsienneto Road, NH Route 28, North High Street, and associated cross streets, extending from the Derry/Londonderry Town Line to 800 feet east of the Pinkerton Street intersection, according to Arcand.

“The work includes a new bridge to carry Folsom Road over Shields Brook,” he said. “The Shields Brook Bridge is a single span structure consisting of metalized steel plate girders with a composite reinforced concrete deck founded on drilled shaft abutments with tensile reinforcement straps behind stem walls.

“This project includes a multi-use path extension of the Derry Rail Trail through the project area, including a grade-separated crossing of Folsom Road via the new Shields Brook Bridge. The work also includes coordinated signal systems, overhead sign structure construction, building/structure demolitions, and construction of water quality treatment areas. We hope to start work on this segment in late 2024 or early 2025.”

The 13065C Project is in the final design stage. Arcand said that work on this phase could begin in 2025. Proposed work for this project includes construction on Tsienneto Road, NH Route 28 Bypass, NH Route 102, and associated cross streets, extending from approximately 800 feet east of the Tsienneto Road/Pinkerton Street intersection to NH Route 102.

“The project includes a new bridge to carry Tsienneto Road over Tributary E,” Arcand said. “The work also involves reconstruction of NH Route 102, including constructing a 3-foot by 6-foot reinforced concrete box culvert and coordinated traffic signals at the Tsienneto Road and Beaver Lake Road intersections, along with coordinated signal systems, overhead sign structure construction, and construction of water quality treatment areas.”

About the 13065A Project, Bates said, “Our first action item was to create access to the site off the northbound side of I-93 in order to begin tree clearing and bulk cut and fills. Blasting was completed on what will be the new northbound on-ramp, to accommodate the added width for the ramp and concrete sound wall. Once overhead utilities were relocated, we were able to begin drilling and blasting on the new Old Rum Trail connector road to generate the material for the fills closer to the new overpass bridge and Exit 4A ramps.

“Foundation work on the easterly bridge abutment began late in 2022. In spring of 2023 the nearly year-and-a-half long process of 287 drilled shafts for sound-wall foundations began. As work progressed on the excavation for Old Rum Trail, we opened up construction on the southbound side. But before we could complete the fill for the southbound on-ramp, we needed to construct and relocate approximately 1,600 linear feet of the Wheeler Pond Tributary stream. As the southbound earthwork progressed so did work on the southbound bridge abutment, and bridge girders were set in December of 2023. This was done with the combination of rolling road blocks for traffic control in the southbound lanes and a temporary detour of northbound traffic over the newly constructed northbound on- and off-ramps.

“With the bulk of earthwork and drainage completed, the final stages of construction on Phase 1 have included paving, curbing, and completing work on the bridge and sound walls.”

He added that the main earth movers on the first phase were two Caterpillar 349 Excavators feeding multiple articulating off-road and tri-axle dump trucks, as well as two Caterpillar D6 Dozers placing the bulk material.

“Other equipment consisted of our primarily Cat fleet of loaders, smaller dozers, Cat 304 to 340 Excavators, and rollers,” Bates said. “Other equipment used included a John Deere 772 Grader, a Volvo EW 180 Wheeled Excavator, two broom tractors, and multiple cranes.”

According to Bates, one key feature of the project is that much of the work is new roadway and out of traffic, allowing the team to focus on production rather than traffic control.

“Also, due to that, we were able to work through the winters with little effect from winter maintenance and plowing on I-93,” he said. “We did relocate approximately 1,600 linear feet of the Wheeler Pond Tributary stream to accommodate the new southbound on-ramp and sound wall. This included intricate design of the construction and stream bypass system as well as weeks of construction.”