The announcement came on Sunday after a video clip published on the “Satisfied to fight” Facebook page on Friday went viral.
The clip shows a soldier holding up his gun to threaten another motorist for overtaking.
It is assumed that the incident took place on an expressway, but the page did not mention its location.
In response, Chief of Defence Forces General Songwit Noonpackdee ordered the soldier’s detention on Saturday and the setting up of a committee to investigate the case.
Armed forces spokesman Lt-General Teerapong Pattamasingh Na Ayuthaya said the soldier had violated several military regulations, including disobeying a commander’s order, failing to observe good manners, using rude language, threatening others and destroying the military’s image.
So far, the following disciplinary action has been lined up for the accused:
• 21-day detention
• No pension contribution for this fiscal year
• 15-day disciplinary training
• No carrying of weapons
Teerapong said the division the soldier has been assigned to has acknowledged his misdemeanour and apologised to the motorist.
“The armed forces has investigated the incident swiftly and fairly,” he said, adding that all commanders have been instructed to screen all their subordinates’ behaviour and discipline to prevent a repeat of this incident.