The Department of Disaster Prevention and Mitigation reported that there were 419 road accidents on Monday, killing 62 and injuring 422 people.
Speeding was the main cause, accounting for 39.4% of accidents, followed by drunk driving (30.55%), the department said.
The vast majority of accidents (86.51%) involved motorcycles and most (85.44%) of them took place on straight roads, followed by highways (38.86%) and rural roads (33.17%).
The highest accident rate was between midnight and 1am.
The 20-29 age group accounted for the highest number of victims, at 17.36%.
Provinces with the highest number of accidents on Monday were Prachuap Khiri Khan and Songkhla, with 15 each.
Bangkok recorded the most road deaths, with five.
Prachuap Khiri Khan, which is home to Cha-am, Hua Hin and other tourism destinations, had the highest number of traffic injuries, at 22.
The long holiday weekend (Friday to Monday) also saw 1,574 injured in a total of 1,570 serious accidents. Kanchanaburi recorded the most accidents over the four days (57) as well as the highest number of people injured (56).
Bangkok saw the highest fatalities, with 13.
Nineteen provinces had registered no road fatalities after day four of the “seven dangerous days”.
The department warned that interprovincial main roads may be congested on Tuesday as people return to cities for the first working day after the New Year break.
Drivers were also urged to check their cars before leaving and to find a safe place to park and rest if they feel drowsy.
The “seven dangerous days” covers the New Year exodus, when millions travel to their hometowns or holiday destinations.