Just finished a trip down to Bangkok and Back to Chiang Mai via Kanchanaburi. Coming down to Bangkok on the east lane of the highway was a very sweet drive, the road where they replaced the old tarmac is pristine and very smooth. The construction has been completed to about 30k North or so from Nakon Sanowhere. Then you hit the old patch section which has not been touched yet, still very rough. The work on the highway interchange on to the 121 bypass around Nakon Sanowhere appears to be complete.

 

The significant construction is now focused on the 121 bypass, you will be funneled down to one lane in both directions on the east side of the highway. We were able to maintain 60kph from start to finish. They have the west side torn up and are replacing the road bed and new paving.

 

Going back to Chiang Mai was as good as the other side except the patch area was a bit longer but not unbearable, a small section of construction still in progress but not a problem. There appears to be a pipeline of some sort going in and there were cones along the shoulder but all work being done off the highway.

 

Enjoy your next ride on this highway still in good shape

I like to miss out busy highways altogether on a motorbike trip unless there's no choice.

2 hours ago, Kwasaki said:

I like to miss out busy highways altogether on a motorbike trip unless there's no choice.

I am the same but this past week lots of bikes on this highway. I stopped and Nakon Sanowhere and at the MickeyDs must have been 10 or 15 big bikes riders taking a break