Police in Tokyo said Thursday they have arrested the 24-year-old driver of a car that hit a woman in Shibuya. The woman, in her 20s, has been in a coma since the accident, TBS reported.

Police said the driver, identified as Masao Watabe, a part-time worker from Kawasaki, has admitted to having smoked a herb just before the accident which occurred at around 5:30 p.m. on May 3. After going through a red light and hitting the woman at an intersection, Watabe crashed into three other vehicles, police said.

Police said they found traces of the herb in Watabe's car after thew accident.

The smoking of “haabu” (herbs), or loophole drugs, sometimes containing hallucinogens, has been a growing problem in Japan in recent years. The unregulated products have caused serious health problems, and even death, while the law has been struggling to catch up.

Last year, the Ministry of Health, Labor and Welfare changed the legal designation of 775 quasi-legal drugs in a plan to combat the growing use of these “herbs” containing 90 separate stimulants and hallucinogens.

© Japan Today