Prime Minister Prayut Chan-o-cha has instructed the National Police Office to step up checks to find drink-and-drive motorists after the triple fatality in Chiang Mai on Sunday.
A drunken motorist rammed her car into a group of cyclists, killing three and injuring two.
Deputy government spokesman Sansern Kaewkamnerd said yesterday the prime minister also wants police to find out where the motorist had been drinking before the accident.
Police have charged university student Phatchuda Jayruan, 23, with reckless driving causing death, damage and injury, said Pol Col Mongkol Samphawaphol, deputy Chiang Mai provincial police chief.
Maj Gen Sansern said if police inquiries show she had been drinking at a night entertainment venue, officers should make sure it complied with its opening hours. He wanted to know how she could still be drunk at 6.15am when she hit the cyclists if the outlet had closed at the correct time.
The driver said she joined a party at a nightspot before heading home in Doi Saket district. She told police she had taken a brief nap on the side of the road before carrying on with her journey. Results of a blood alcohol test showed she had 67 milligrammes of alcohol per 100 millilitres of blood, over the legal limit of 50 mg.
Suriya Prasatbandit, Chiang Mai governor, yesterday visited Supol Tasing, 56, one of the two injured victims at Maharaj Nakorn Chiang Mai Hospital.
During the governor's visit, Mr Supol was seen holding up a placard reading: "Drink-driving is equivalent to murder". The governor said he was sorry about the accident and would crack down on nightspot opening times.