SWAMPSCOTT – What started as a routine traffic stop on Humphrey Street late Sunday night turned into a drug bust.David Aronson, 41, 11 Ernest Ave., Quincy was arrested and charged with trafficking cocaine, possession within 1,000 feet of a school zone, violation of town knife bylaw as well as driving an unregistered and uninsured motor vehicle.According to Detective Sgt. Timothy Cassidy, Officer Michael Fraylor stopped a Mercedes 300E on Humphrey Street Sunday at approximately 11:30 p.m. for being unregistered and uninsured. Cassidy said Frayler ran a check and found Aronson had an outstanding warrant for larceny under $250. Officer Thomas Hennessey and Sgt. William Waters Jr. assisted with the arrest.”When he was being placed under arrest Frayler asked if he (Aronson) wanted any personal items from his vehicle before it was towed,” Cassidy said. “He told Frayler he wanted his backpack that he would give to a female acquaintance, who was not at the scene yet.”Cassidy said the backpack was open when it was retrieved and the officers at the scene saw packets of what appeared to be cocaine inside.”We found 21 packets of suspected cocaine totaling 14.2 grams,” Cassidy said. “We also found a knife. Aronson was arrested and held overnight.”