How This Report Was Researched
This report draws on publicly available government program data, state registration records, and direct expert commentary from Freehome Service Center. Figures are derived from the source data and stated assumptions described below.
Primary Data Sources
Georgia Clean Air Force (GCAF)
GCAF administers Georgia's mandatory OBD emissions testing program across the 13-county Atlanta metropolitan area. Program data provided statewide testing volume and the 10-15% first-test failure rate range used for local failure estimates.
Georgia Department of Revenue
Vehicle registration data was used to establish the eligible testing population in Forsyth and Cherokee County, including approximately 202,500 eligible gasoline-powered vehicles in Forsyth County and approximately 222,500 in Cherokee County.
U.S. Environmental Protection Agency OBD Program Data
National OBD fault-code frequency distributions were sourced from EPA OBD program data. The EVAP system failure rate of 24.3% originates from this federal dataset and was applied proportionally to local failure estimates.
Freehome Service Center
Repair cost figures and expert commentary were provided by the owner of Freehome Service Center, an ASE Certified technician and NAPA Auto Care Center operator on Cumming Highway in Forsyth County.
Time Period
Data references reflect the most current available figures as of the 2026 publication date of this report. The Georgia repair waiver threshold of $1,176 reflects 2026 Georgia law.
Analysis Approach
The approximately 50,000 annual first-test failure estimate was calculated by applying the Georgia Clean Air Force statewide first-test failure rate range of 10% to 15% to the 425,000-vehicle eligible population. This produced a range of 42,500 to 63,750 failures and a midpoint of approximately 50,000. Failure subtotals by fault-code category were derived by applying EPA national fault-code distribution percentages to that midpoint estimate.
Limitations
National EPA OBD fault-code distributions may not precisely mirror the Forsyth and Cherokee County failure mix. Local environmental factors documented by Freehome Service Center are not captured in statewide or federal datasets. Repair cost figures reflect one shop's current pricing and may vary by vehicle make, model, parts availability, and repair complexity.