The 71km long expressway of LEKAS is planned as an alternative route to the toll free section of North South Expressway between Prai and Penang Island. It has been developed primarily as an expressway link to maintain the comfort and safety of travel along the NSE. As a bypass link, the LEKAS is also anticipated to provide improved accessibility to the southern region of Kedah, specifically the catchments of Kulim, Lunas, Bandar Baharu and Padang Serai. In addition, the Southern Kedah Expresssway is also expected to enhance the connectivity to the Butterworth-Kulim Expressway.

LEKAS which is a closed toll highway has been planned to cater for more efficient and smooth flow for the through traffic along the NSE. In addition, this new expressway is planned to improve the accessibility for the various townships and catchments of Southern Kedah, namely, Bandar Baharu, Kulim, Lunas, Padang Serai and Terap. The expressway is also expected to further enhance the linkage and accessibility of not only the BKE but also the Kulim High Tech Industrial Park.