FHWA Noise Abatement Reference

Return the federal highway-noise criterion context for common receptor categories.

Description

The federal Activity Category B exterior criterion for residential uses is 67 dBA Leq(h); impact policy also considers substantial increase under the state procedure.

The federal Activity Category B exterior criterion for residential uses is 67 dBA Leq(h); impact policy also considers substantial increase under the state procedure. This reference explains the selected concept and the evidence needed to interpret it.^{[1, 2]}

The returned values include Source, Statement, Topic. The How section below explains the calculation, input rules and interpretation.

When to use FHWA Noise Abatement Reference

Use FHWA Noise Abatement Reference when you need to evaluate the supplied records under the calculation and evidence rules below. The Noise Abatement Criteria are impact-evaluation triggers, not design goals or absolute federal property-line limits. This is an introductory excerpt, not the complete standard, a current compliance check or a project-specific calculation.

Choose the measured quantities, units, weighting and measurement basis before entering values. For a reference, select the exact topic. For a catalog lookup, prepare complete source-backed records; for a screen, select an applicable caller limit.

How to use FHWA Noise Abatement Reference and understand its results

Choose the measured quantities, units, weighting and measurement basis before entering values. For a reference, select the exact topic. For a catalog lookup, prepare complete source-backed records; for a screen, select an applicable caller limit.
Enter topic using the field table and calculation rules, then run the tool.
Read source, statement, topic. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
topic	Reference topic to return.	string; one of "category-b", "category-c", "caution"	Required

Choose one of the exact topic values in the table. The tool indexes a fixed, locally embedded reference entry and returns its source label, statement and unchanged topic. It does not fetch the source or update the wording. Topic meanings and all returned entries are shown below.

Selection	Returned reference entry
category-b	source: 23 CFR Part 772, Table 1; statement: The federal Activity Category B exterior criterion for residential uses is 67 dBA Leq(h); impact policy also considers substantial increase under the state procedure.; topic: category-b
category-c	source: 23 CFR Part 772, Table 1; statement: Activity Category C includes exterior areas such as schools, parks, and places of worship and also uses 67 dBA Leq(h) in the federal table.; topic: category-c
caution	source: FHWA Highway Traffic Noise guidance; statement: The Noise Abatement Criteria are impact-evaluation triggers, not design goals or absolute federal property-line limits.; topic: caution

selected exact topic → embedded source label, explanatory statement and topic

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
source	Source used for the reference statement.	string
statement	Narrow reference statement for the selected topic.	string
topic	Selected reference topic.	string; one of "category-b", "category-c", "caution"

json

{
  "input": {
    "topic": "category-b"
  },
  "output": {
    "source": "23 CFR Part 772, Table 1",
    "statement": "The federal Activity Category B exterior criterion for residential uses is 67 dBA Leq(h); impact policy also considers substantial increase under the state procedure.",
    "topic": "category-b"
  }
}

Limitations and assumptions

The Noise Abatement Criteria are impact-evaluation triggers, not design goals or absolute federal property-line limits. This is an introductory excerpt, not the complete standard, a current compliance check or a project-specific calculation.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing fields without a declared default, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Festival Noise Limit Screen: An event noise screen can conservatively add an explicit uncertainty allowance to a measured level before comparison. All values need the same weighting and assessment interval. For a complementary task, use Microphone Placement Reference: Microphone height and distance from façades or other reflecting surfaces must follow the stated measurement standard and assessment objective. This reference explains the selected concept and the evidence needed to interpret it.

Further background: Highway noise policy and activity categories.

References

FHWA Noise Abatement Reference — tool.io
Highway noise policy and activity categories — Federal Highway Administration

Similar or alternative tools

Festival Noise Limit Screen
An event noise screen can conservatively add an explicit uncertainty allowance to a measured level before comparison. All values need the same weighting and assessment interval.
Microphone Placement Reference
Microphone height and distance from façades or other reflecting surfaces must follow the stated measurement standard and assessment objective. This reference explains the selected concept and the evidence needed to interpret it.