 Then it widens to a four-lane dual carriageway and continues to Surat Thani, Amphoe Kanchanadit.It enters Nakhon Si Thammarat province at Amphoe Khanom, but does not pass the town of Khanom.It, then, goes southward pass Amphoe Sichon, Amphoe Tha Sala and ends at Ban Tha Pae, about 10 km north of Nakhon Si Thammarat.