Pre-1992 TLC charge, rule text not online (often in unlicensed-vehicle cases)
This code comes from the TLC's rule numbering used before mid-1992. The text of that rule is not available online (not on nyc.gov or in web archives), so we cannot say exactly what it covered. OATH's public records show it on 3,529 charges, with violation dates between Jan 2, 1992 and Jun 30, 1992. Almost all were written by TLC inspectors. The respondents were almost all individual people, which suggests a rule aimed at drivers. It was usually charged together with 506B/506C/506D (NYC Admin. Code §19-506, unlicensed for-hire activity), so it was most likely part of an unlicensed-vehicle case. Your summons or hearing decision describes the specific conduct.
TLC rule numbering used before mid-1992 (text not available)TLC – Old Rule Book Chapters (nyc.gov)