That's a staggering number, but isn't the article including the whole country in this count of 256 deaths? It sounds like "only" 12 of them were in Bangkok:
> Over the Dec 27-31 period, Bangkok had the highest number of deaths at 12
(...which implies a very long tail of cities outside of the capital.)
> A total of 256 were killed and 2,588 injured in 2,529 road accidents nationwide from Dec 27 to 31
https://www.bangkokpost.com/thailand/general/1827019/seasona...