NHDOT Spaulding Turnpike Open Road Tolling

Under an on-call contract with the New Hampshire Department of Transportation (NHDOT), HMMH performed the traffic noise analysis for the proposed Open Road Tolling Project on the Spaulding Turnpike (Route 16) in Dover and Rochester, New Hampshire. The study evaluated two alternatives to replace the existing toll plazas: an Open Road Tolling (ORT) alternative and an All Electronic Tolling (AET) alternative.

As part of the worst noise hour determination, HMMH processed weekly traffic count data for existing conditions (2016) and discovered that ten of the 12 busiest weeks of the year occurred during the summer months. This was the case at both of the existing toll plazas. In addition, our analysis of hourly traffic count data demonstrated that the turnpike is a directional facility, with predominantly southbound flow in the morning and northbound flow in the afternoon. Consequently, the worst noise hour determination considered both the a.m. and p.m. peak hour for two of the busiest weeks of the year. One week representative of periods dominated by recreational traffic (primarily the summer months of July and August) and the other week representative of periods dominated by commuter traffic.

HMMH used the latest version of the FHWA Traffic Noise Model (TNM) for all noise level calculations and noise barrier analyses. The modeling of traffic noise at the toll plazas was consistent with the guidance and best practices for modeling accelerating and decelerating vehicles contained in NCHRP Report 311:Predicting Stop-and-Go Traffic Noise Levels and NCHRP Report 791: Supplemental Guidance on the Application of FHWA’s Traffic Noise Model.

HMMH evaluated the feasibility and reasonableness of noise barriers wherever noise impact was expected. Noise barriers were found to be feasible and reasonable at two locations along the Project Corridor.