N.Y.C. Admin. Code § 17-607: § 17-607 Post-accident testing.

a. A drug test must be administered to any bus driver who, during the course of his or her employment, (i) is involved in a serious accident while operating a bus or other motor vehicle; or (ii) during any twelve month period, is involved in three or more accidents while operating a bus or other motor vehicle, regardless of the amount of property damage caused or injuries sustained.

b. The specimen for a post-accident drug test required by this section shall be collected as soon after the accident as is practicable, but not later than thirty-two hours after the accident. In those cases involving testing under paragraph (ii) of subdivision a of this section, the specimen shall be collected in accordance with the requirements of this subdivision after the third accident.