EASTHAMPTON – The Planning Board’s continued discussion on a proposed Dunkin’ restaurant on East Street was postponed to allow the developer to review the city’s peer review of their traffic study.

Emanuel Sardinha, owner of American Dream Realty LLC, is seeking a special permit as well as a stormwater management permit in order to build the 1,912-square-foot dine-in and drive-through restaurant at 5 and 9 East Street, near the intersection with Route 5. The public hearing was initially scheduled to continue on Aug. 25, but at the request of R. Levesque Associates on behalf of American Dream Realty, it was continued until Sept. 22.

At the public hearing on July 21, the planning board voted to approve a peer review of McMahon Transportation Engineers and Planners’ traffic study. Fuss & O’Neill was contracted to conduct the peer review, which was completed and sent to City Planner Jeffrey Bagg on Aug. 21.

The contents of the original traffic study were a substantial part of the July public hearing. Fuss & O’Neill found, for the most part, the parameters of McMahon’s study were “in accordance with standard practice,” but did have some recommendations for additional information.

“We have consulted with McMahon Associates regarding the additional information suggested in the Fuss and O’Neil letter and they feel they will be able to complete the additional work requested in early September leaving ample time for F&O to review their findings,” R. Levesque Associates Director of Operations Sofia Bitzas wrote in the company’s request for a continuance.

McMahon gave an estimate of 80 vehicles on an hourly basis with the majority of the traffic being preexisting. Jeff Bandini,  the firm’s transportation project manager, said while the traffic data had been collected on Jan. 23, the firm adjusted the data by 9 percent to account for additional warm-weather travel. Fuss & O’Neill indicated in their peer review that McMahon’s seasonal adjustment factor of 9 percent was higher than the Massachusetts Department of Transportation’s (MassDOT) 1 percent for January.

“The seasonal adjustment is therefore conservatively high and acceptable for analysis,” the study read.

But Fuss & O’Neill also pointed out the intersection of East Street and Route 5 are already operating at level of service F (LOS F) “in the existing, no build, and build a.m. and p.m. peak hour scenarios,” meaning the traffic flows exceed capacity during those times. The firm also noted that while a “major capital investment would be needed to improve peak hour traffic, MassDOT may not make those improvements by 2027, the end of the study’s analysis time frame.

“The significance of LOS F at unsignalized intersections is that drivers experiencing excessive delay may choose to accept smaller than normal gaps in the conflicting traffic stream through which to execute turning movements,” according to the report. “This could result in negative safety impacts that would be exacerbated by the additional turning movement demand produced by the project. In lieu of implementation of capacity improvements to address the existing operational efficiencies, the project should be requested to recommend and commit to execution of mitigation measures to enhance vehicular, pedestrian, or bicycle safety in the study area.”

The peer review also raised concerns that queues of vehicle approaching Route 5 from the west seeking a left turn during peak morning hours are currently 668 feet long. Those queues are 206 feet long during evening peak hours. By 2027, those lines project to be 820 and 284 feet long, respectively without a Dunkin’ at the location and 1,014 and 326 feet long, respectively, in a build scenario. Fuss & O’Neill noted the proposed Dunkin’s driveway would be approximately 280 feet from the intersection and suggested the city request an operational analysis on the effects of East Street queues.

“If the peak period queuing will typically obstruct driveway operations, measures should be considered to correct this,” the report stated.

A signal warrant analysis was also not part of the initial study and was something Fuss & O’Neill suggested “to better understand feasible alternatives to improve the operational conditions at the intersection of East St and Route 5.”

The firm also suggested clarification on McMahon’s use of a formula for calculating pass-by rates as opposed to a more conservative model as well as reasoning for why McMahon did not provide separate trip distribution share data for morning and afternoon periods.