Fire Station: Engineers Present Driveway, Signage Options to Planning Board
Gary Hebert, transportation engineer with Fay, Spofford & Thorndike, presented his peer review comments to the Planning Board Thursday night during the Site Review Plan for the proposed new Center Fire Station. He stressed that the site driveway at the intersection with Farmers Row assumes that when the largest trucks are entering or leaving the fire station driveway at Farmers Row, that all traffic will be stopped and that the driveway will have no conflicting traffic exiting or entering the site. The plan right now shows that when a fire truck enters or exits the station and turns onto Farmers Row, it will encroach into the opposing lane of traffic.
Hebert said that this option may be the greenest from an impervious surface coverage perspective, and has the least impact on the root structures of the two large maple trees in either side of the proposed driveway. "The drawback of this option is that the green areas adjacent to the site driveway could be encroached upon by the ladder fire truck drivers. He suggested that an arborist look at the impact on the tree roots if an increase in width were proposed.
Hebert recommended that the Center Fire Station Committee consider a 20 to 25-foot turning radii at Farmers Row rather than the proposed 12-foot radii shown on the plan. "If you don't want trucks to encroach on the other lane, it involves much more (width)."
Fire Chief Joe Bosselait said that fire trucks have a 45-degree 'cramp angle' and because of this the driveway could be kept at 15 to 18 feet wide. Hebert responded that with a 42-foot vehicle that is 8 feet wide, it needed to be verified.
Hebert recommended that the applicant provide a plan view elevation of the sight distance at the entrance to the site based on an accurate field count of speeds and volumes using an automatic traffic recorder. "Based on the field measurements, it may be possible to see at least 375 feet in both directions from the centerline of the future driveway by looking around the utility poles," he said, adding that the best solution might be to remove them altogether and put them in underground.
He added that better sight lines would be important when cars estimated at traveling at 45 mph have to stop quickly and recommended that the poles be relocated.
In his written report to the Planning Board, Hebert said, "FST understands that the Applicant has requested that a standard traffic impact study requirement be waived for the Center Fire Station relocation. We anticipate that the new peak hour traffic volumes will be minimal, typically fewer than eight-10 trips during commuter peak hours. Based on the assumption that the staffing requirements for the site will be minimal, we anticipated that the typical impact will involve fewer than 50 vehicle trips on a daily basis, of which 2 to 3 round trips would typically involve emergency vehicles, primarily ambulance calls rather than fire emergency calls. Fire emergency calls should average less than 1 per day in accordance with the historical records of fire and ambulance calls provided by the Groton Fire Department."
Hebert addressed signage and signals. "We recommend that the Committee, at a minimum, provide advanced warning signage in both directions, about 300 ft. to the north and 300 ft. to the south, to alert motorists that an emergency station exists. Concurrently, both Farmers Row approaches to the driveway should be augmented by two yield lines located 50 ft. away from the driveway on both approaches with a sign and an arrow to alert motorists where to stop in the event of an emergency."
He also mentioned possible use of an emergency hybrid beacon that will stay dark until it is activated by the emergency station, although, depending upon the need, this could be a last resort depending upon the number of calls to the emergency station.
In closing, Hebert said that if possible, the curve radii of the driveway should be increased to address the needs of the largest emergency vehicles. "Ideally, the largest vehicles should be able to enter and leave the site without encroaching on opposing traffic lanes on Farmer's Row."
The Historic District Commission, in a letter to the Board, also weighed in and enumerated some of the issues that will still need to be addressed by the Station Design team. These include elimination or reduction of driveway illumination with emergency lights turned on only when needed, and that "the access driveway from Farmers Row will not be illuminated."
Secondly, the HDC letter said the commission had significant concerns with the modular retaining wall being proposed along the upper south edge of the property.
Thirdly, the HDC believes that various paving materials still need to be introduced to reduce the visual effects of a large expanse of pavement.
Fourth, alternative design considerations still need to be given to the edges of the access drive from Farmers Row.
Fifth, the landscape plan should be composed of indigenous trees and plantings, not ornamental plantings.
Sixth, screening for the parking along the south side of the station has not yet been addressed.
The design team for the proposed station was present including Don Walter of Dore & Whittier and john Perry from Gale Associates. Perry explained that the team is proposing an 18,785 sq. ft. station with four double-deep bays and an area set aside for future living quarters. The building is being designed to fit into the agrarian area.
Of the 11-acre parcel owned by the Lawrence Homestead Trust, the station will be built on a 2.8-acre portion. The actual footprint of the building is 13, 860 sq. ft. with 27 parking spaces, three of which are handicap accessible.
Perry said, "All vehicles will back into bays with smaller vehicles in the back. We want to maintain the open space as much as we can," he said. Snow storage will be located in the front and back and anything over five feet will have to be trucked off site. The plan calls for using a natural looking block wall, like fieldstone, with sidewalks on the side.
He stressed that little had changed from the original submission to the Board. The building elevation is at average grade on site to keep the building as low as possible.
The building is 16 ft. from the sideline on the north and 76 feet from the sideline on the south. The structure is not higher than 365 feet but it will feature a cupola.
The Board continues the hearing on the Site Plan Review to Oct. 25 at 7:30 p.m.