CTE Environmental Impact & Sustainability 2 — Questions and Answers
Question 1: The FHWA highway traffic noise model used for noise impact assessments is called:
- TNM (Traffic Noise Model) (Correct answer)
- FHWA RD-77-108
- HNM (Highway Noise Model)
- SoundPlan
Correct answer: TNM (Traffic Noise Model)
The FHWA Traffic Noise Model (TNM) is the agency's approved computer model for predicting highway traffic noise levels and evaluating the feasibility and reasonableness of noise barriers.
Question 2: At what noise level (Leq) does FHWA consider a highway noise impact to occur for Category C land use (residential)?
- 52 dB(A)
- 66 dB(A)
- 67 dB(A) (Correct answer)
- 75 dB(A)
Correct answer: 67 dB(A)
FHWA's noise abatement criteria establish 67 dB(A) Leq as the impact threshold for Category C land uses, which include residences and similar noise-sensitive outdoor areas.
Question 3: What is the purpose of an 'alternatives analysis' in a highway EIS under NEPA?
- To select the lowest-cost design option
- To evaluate a range of reasonable alternatives including the no-build alternative (Correct answer)
- To satisfy Section 106 historic preservation requirements
- To determine the traffic design year volumes
Correct answer: To evaluate a range of reasonable alternatives including the no-build alternative
NEPA requires an EIS to rigorously evaluate a reasonable range of alternatives, including the no-build alternative, to inform decision-makers and the public about tradeoffs.
Question 4: Which greenhouse gas is the primary concern from mobile source emissions in the transportation sector?
- Methane (CH4)
- Nitrous oxide (N2O)
- Carbon dioxide (CO2) (Correct answer)
- Hydrofluorocarbons (HFCs)
Correct answer: Carbon dioxide (CO2)
Carbon dioxide (CO2) from combustion of gasoline and diesel fuels is the dominant greenhouse gas from the transportation sector, accounting for the largest share of US transport GHG emissions.
Question 5: What does 'environmental justice' require in federally funded transportation planning?
- Equal distribution of transportation projects across all counties
- Identifying and addressing disproportionately high adverse effects on minority and low-income populations (Correct answer)
- Eliminating all tolls in low-income communities
- Requiring minority-owned firms to manage EIS studies
Correct answer: Identifying and addressing disproportionately high adverse effects on minority and low-income populations
Executive Order 12898 requires federal agencies to identify and address disproportionately high and adverse human health or environmental effects on minority and low-income populations.
Question 6: What is a 'categorical exclusion' (CE) in the NEPA process for transportation projects?
- A project excluded from NEPA review by congressional exemption
- An action that does not individually or cumulatively significantly affect the environment (Correct answer)
- A project with impacts confined to the right-of-way
- An exemption from Section 404 wetland permits
Correct answer: An action that does not individually or cumulatively significantly affect the environment
A CE is a NEPA determination that a category of actions does not have significant environmental effects, allowing projects to proceed without an EA or EIS.
CTE Environmental Impact & Sustainability 2
The FHWA highway traffic noise model used for noise impact assessments is called: