Taiwan Provincial Highway No. 18, which connects from Chiayi City to Alishan, formerly used to have a length of 90 km to directing to Provincial Highway No. 21 at Tatajia, Yushan National Park. It is also called as New Central-Crossing Highway and Alishan Highway.
Now, West Terminal has been extended to THSR Chiayi Station called as HSR Avenue in Taibao City, to contacting between downtown Chiayi and HSR station. Therefore, the overall length of Provincial Highway No. 18 is 109.985 km.