Project Number:

3066

MassHighway: I-93/Route 110/Route 113 Interchange

SERVICE:

Air Quality & Noise Analysis for Highway Reconstruction

DESCRIPTION:

Te­ch Environmental provided air quality and noise studies to the Massachusetts Highway Department, as a sub-consultant to Jacobs Engineering Group, for reconstruction of the I-93/Route 110/Route 113 highway interchange in Methuen (the Methuen Rotary). These studies were prepared as part of the federal EA and State EIR published for the project. Tech provided expert testimony in public hearings. The Jacobs/Tech Environmental team completed the combined EA/EIR and received final approvals on that document from both the State and FHWA within 18 months from receiving a Notice to Proceed.

The noise analysis was conducted in accordance with FHWA Procedures for Abatement of Highway Traffic Noise and Construction Noise (23 CFR 772) and with the MassHighway Type I Noise Abatement Policy and Procedures. Sound monitoring was done to establish the Noisiest traffic Hour in the project area. Baseline sound level monitoring was then performed in adjacent residential areas, the results from which were used to calibrate the FHWA TNM noise model. Future sound levels were predicted at 100 sensitive noise receptors for the No-Build and two Build Alternatives in the year 2030. Locations potentially affected by traffic noise impact were identified, and a noise barrier analysis was performed for each residential location with a traffic noise impact. Hundreds of potential barrier designs were analyzed. Two barrier options were recommended for each of the northeast and southeast quadrants of the highway interchange that were feasible (achieving a minimum 7-dBA insertion loss at a front-row home) and economically reasonable (costing no more than $2,700 per dBA reduced per housing unit).

The air quality analysis included both a mesoscale and Microscale analysis of the entire traffic study area. The mesoscale analysis proved future Build Alternative air pollutant emissions will be lower than future No-Build emissions and established the fact that the roadway project will improve regional air quality. The Microscale analysis confirmed compliance with the National Ambient Air Quality Standards for carbon monoxide (CO).

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Key Points

  • The Massachusetts Highway Department's reconstruction of a rotary at the junction of three highways required air quality and noise analyses to proceed.
  • Tech performed extensive air quality and noise analyses to confirm that the project would meet FHWA and MassHighway noise standards, as well as air quality standards and NAAQS for carbon monoxide.