Noise & Air

      The Traffic Noise/Air Quality Section provides specialized highway technical expertise in the areas of highway traffic noise and air quality. These are two environmental issues addressed in the transportation planning process that the public has shown increasing interest and concerns in recent years. The traffic noise analysis includes the following:

• Identification of land uses that may be affected from the proposed highway
• Prediction of traffic noise levels, often 20 years in the future (Design Year)
• Determination of existing noise levels in the vicinity of the proposed alignment
• Determination of traffic noise impacts
• Examination and evaluation of noise abatement measure for reducing or eliminating the noise impacts, giving weight to the benefits and cost of abatement, and to the overall social, economic and environmental effects

      All noise mitigation measures that are determined to be reasonable, feasible and cost-effective are included into the highway project.

      The air quality analysis determined the influence of a proposed highway project on the air quality in the project area (project-level analysis). The only pollutant that can be readily analyzed at this level is carbon monoxide. Some key elements of an air quality analysis are:

• Determination of appropriate evaluation years and receptor locations
• Computation of average operating speeds, traffic flows and movements
• Determination of highway mobile source emissions for evaluation years
• Computation of air quality concentration at the identified receptor locations
• Comparison of these concentrations to the National Ambient Air Quality Standards

      All analyses are conducted in accordance with Federal and State laws and relations pertaining to highway traffic noise and air quality. Our Section also provides coordination and quality control for traffic noise and air quality studies undertaken by private engineering firms.