The complete cross-island link consists of three sections: the main highway, a 194.2 kilometer route from Tungshih in the west to the Suao-Hualien Highway on the east coast; a branch running north from Lishan to Ilan; and a spur road from Wushe.
完成後的中部東西橫貫公路路線分為主線、支線和供應線等三個部分。主線係由東勢經達見、梨山越大禹嶺，再循立霧溪經關原、碧綠、慈恩、天祥至太魯閣，最後銜接蘇花公路，全長共一八五公里。支線由梨山北行至宜蘭；供應線則自霧社、經昆陽至大禹嶺與主線相連。