Bro, Straight road from kai katti goes to Muthupet and Nagapattinam. Chidambaram Bus you travelled from Adhirampattinam will take this route to go to Nagapattinam. From that junction, you have to take right, which is not a highway but a street road which links Adhirampattinam Road. Your bus took left which goes to Mannargudi via Madhukkur...Thanks