Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
traffic [ˈtræfɪk] n (of people, vehicles) движе́ние; (of drugs etc) нелега́льная торго́вля
vi
to traffic in (liquor, drugs) нелега́льно торгова́ть*(impf) +instr
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.