Hello, Currently, route 340 is a trunk road. So, route 347 in the section before the interchange in Bang Pahan can be trunk road and it also meets the condition that define in the guideline.

Hello, according to the guideline

Any road section* that is more than 90% dual-carriageway, has a physical or painted median (wider than 1m, not just a double solid line) and shoulder, and is more than 25km long.

Example route 2050 is currently set as a primary route. So this route can be this classification.

Hello

what source did you use for the updated ref number?
- The source I used is from department of highways’ website.
https://roadnet2.doh.go.th/

how did you decide to change the highway classification from primary to secondary ?
- The highway that I changed to is a four digit highway (Highway 1352), thus, I changed the classification to secondary according to this guideline. >> osm.wiki/WikiProject_Thailand#Highway_classification