A. When a juvenile and domestic relations district court or circuit court has adjudicated any case involving a child subject to the jurisdiction of the court hereunder, except for a traffic violation, a violation of the game and fish law, or a violation of any city ordinance regulating surfing or establishing curfew violations, the court before final disposition thereof may require an investigation, which (i) shall include a drug screening and (ii) may, and for the purposes of subdivision A 14 or 17 of § 16.1-278.8 shall, include a social history of the physical, mental, and social conditions, including an assessment of any affiliation with a criminal street gang as defined in § 18.2-46.1, and personality of the child and the facts and circumstances surrounding the violation of law. However, in the case of a juvenile adjudicated delinquent on the basis of an act committed on or after January 1, 2000, which would be (a) a felony if committed by an adult, or (b) a violation under Article 1 (§ 18.2-247 et seq.) or Article 1.1 (§ 18.2-265.1 et seq.) of Chapter 7 of Title 18.2 and such offense would be punishable as a Class 1 or Class 2 misdemeanor if committed by an adult, the court shall order the juvenile to undergo a drug screening. If the drug screening indicates that the juvenile has a substance abuse or dependence problem, an assessment shall be completed by a certified substance abuse counselor as defined in § 54.1-3500 employed by the Department of Juvenile Justice or by a locally operated court services unit or by an individual employed by or currently under contract to such agencies and who is specifically trained to conduct such assessments under the supervision of such counselor.