This research is a study of the problem of transport routes. With a case study of the Post Office is khong Ngae Tambon Pangla Amphoe Sadao Songkhla Province. Which are intended to improve transportation routes. And reduce costs in a postal transport. With steps ranging from using GPS To find the coordinates of each customer, and use Google Map To find out the distance between each customer. And applying the Clark-Wright Saving Heuristic. In order to calculate a new route. The results showed that the original car route from the 12.267 kilometers. To reduce the remaining 12.148 kilometers or fell 0.119 kilometers. Accounted for 0.9% or you can reduce expenses, down 0.97 baht/one way. After that has been done to improve the route using program Lingo. The study found that can set a new route. Distance, down from 12.267 kilometers. Only 8.88 kilometers or 3.387 kilometers, Accounted for 38% Or you can reduce the expenses down 3.2176 baht/one way.