The Buriram - Surin road is/was very narrow, and overtaking motorbikes was often difficult. That being said, this road widening, and practically every other major road exiting Buriram, currently being widened are being done at the expense of the 24 from Nang Rong - Prasat. Wrong priorities!
However, I did see a large poster in Prasat this week which announced that construction of a dual carriageway between Prasat and Prakhonchai will commence this year. (most likely 31st December!)