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Project Experience: I-64 Hampton Roads Bridge-Tunnel Study, Virginia

The Challenge

The Virginia Department of Transportation (VDOT) and the Federal Highway Administration (FHWA) are conducting a study of the I-64 Hampton Roads Bridge Tunnel corridor from I-664 in Hampton to I-564 in Norfolk (approximately 11 miles) to address capacity and roadway deficiencies in the corridor. Study Alternatives will be evaluated using several criteria including potential environmental impacts. HMMH supported the Draft EIS with noise and air quality analyses under an aggressive schedule, producing technical reports in time for review and comment. VDOT and FHWA released the Draft EIS in December 2012 for public review. HMMH will be preparing further noise and air quality analysis to support the Preferred Alternative in the Final EIS.

The Solution

Because this project was identified as one with High Potential MSAT Impacts due to projected traffic volumes, HMMH conducted a quantitative mobile source air toxic (MSAT) analysis estimating net emission increases or decreases compared to the No-Build conditions within the study. The analysis was conducted for eight air toxics for both the interim build year of 2020 and the 2040 design year. The quantitative MSAT analysis demonstrated that there would be no long-term adverse impacts associated with the Study Alternatives. In addition, an air quality assessment was conducted for the proposed tunnel to estimate in-tunnel concentrations of carbon monoxide (CO) for peak hour and incident (idle) conditions. The analysis demonstrated that predicted in-tunnel concentrations of CO would be below the one-hour CO NAAQS of 35 ppm and also below the 15-minute FHWA/EPA guideline of 120 ppm for both the peak hour and incident condition.