Police arrested 88 motorcyclists and seized 94 motorcycles on Friday on suspicion that they illegally modified their bikes for road racing.
Pol Maj Gen Nithithorn Jintakanon, traffic police chief of the Metropolitan Police Bureau, held a press conference at the Metropolitan Police Division 3 at 11.30pm to announce the arrests.
This week, police set up road checkpoints in Metropolitan Division 3 on Friday night to crack down on road racing.
He said 19 of the arrested motorcyclists were under 18 years old. One of 19 young riders also tested positive for methamphetamine abuse, he added.