It is the longest freeway in Taiwan with a total length of 431.5 km (268.1 mi).

This freeway mostly serves as a bypass to major cities in Western Taiwan, traveling through suburban and rural areas.

Connections to downtown Taipei are available through Huandong Blvd (Chinese: 環東大道) in Nangang and Freeway 3A in Wenshan.

In Yingge, the freeway meets National Freeway 2 which provides connections to downtown Taoyuan as well as Taipei's main international airport, Taoyuan International Airport.

In Taoyuan, the freeway is mostly parallel to Provincial Highway 3, traveling through the mountainous areas of the city.

The highway continues to parallel Freeway 1 as it travels along the eastern parts of Chiayi County and Tainan.

In Kaohsiung the freeway bypasses the downtown area and travels along the mountainous rural districts.

Connections to downtown and Kaohsiung International Airport are available through National Freeway 10, which the freeway intersects in the rural district of Yanchao, as well as Provincial Highway 88 in the urban township of Chaozhou in Pingtung County.

The original plan was only intended to build a second freeway between Taipei and Hsinchu.

Extension from Hsinchu SIC to Xiangshan IC was finished in February 1996.

[2] Bad hillside anchoring was blamed as a possible cause, as it had not been raining at the time of the collapse and an earthquake was not registered.

Repairs to the freeway were completed on 19 June 2010 and normal traffic flow restored.