2008 Enhanced I/M Program Annual Report and 2007-2008 Biennial Report: Appendix E

Procedure to Sort the DMV Registration File and Matching of Emissions Inspections I/M Program Evaluation

Obtain a statewide registration database from the NYS DMV (March 19, 2009).
Delete registration records associated with "duplicate" VINs to ensure only unique VINs.
Delete registration records for vehicles exempt from emissions testing based on registration type code. (see REGISTRATION TYPE CODES).
Delete registration records for those vehicles with a VIN containing less than 17 digits.
Delete registration records for those vehicles registered as diesel, electric, "Other," and blank fuel types.
Delete registration records for vehicles exempt from emissions testing due to model year. For purposes of this evaluation, remove from consideration the 3 newest MYs using the calendar year of the registration query. For example, given a March '09 registration run, ignore the 2007, 2008, and 2009 model years. Note that MY 2007 vehicles were exempt from emissions testing in CY 2008). Also, remove from consideration those vehicles older than 25 model years old. Considering a March '09 registration query, ignore vehicles with model years 1983 and older.
Delete the registration records for vehicles with a registered weight (actually seating capacity) from "11"- "100", inclusive. This will remove buses with a seating capacity greater than 11 that are inspected by the NYSDOT.
Sort the remaining registration records into two tables, Upstate (53 counties) and NYMA (9 counties) using the registration "county code. "
Remove the registration records for exempt vehicles with a registered weight over 18,000 lbs from the Upstate table.
The resulting tables represent those vehicles subject to either NYTEST or NYVIP emissions testing based on registration data.
Obtain all NYTEST and NYVIP emissions inspections completed during the previous 15 months (from the date of the registration query), and 2 months after the date of the query.
Using the unique VINs from the screened Upstate and NYMA registration tables, search the statewide NYVIP and NYTEST inspection databases to "find" a passing emissions test (initial or re-inspection) result. For the NYVIP records, this evaluation is based on a pass value ("P") as reported within the "Initial Emission Inspection Results" field. For the NYTEST records, this evaluation is based on a pass value ("P") as reported within the "Initial Emission Inspection Results" or "2^nd Chance Inspection Results" fields.
Tabulate and graph the inspection vs. registration compliance percentages by model year for each I/M area. Use the registration file for both vehicle MY and I/M area.