Extension to Nangang is not the final extension of Taiwan High Speed Railway. Extension from Zuoying to Kaohsiung or Pingtung is also planned.
Taiwan High Speed Rail has already deprived passengers from Taiwan domestic flights to result in no air flights between side Taiwan Island. But, it also aim to compete with Taiwan Rail Administration, Express buses, or personal vehicles by extension.
Though extension or inauguration of high speed rail is taken up as a way to make conventional paralleling rail decline faster in Japan, both of Taiwan High Speed Rail and Taiwan's conventional railway(Taiwan Railway Administration) try to coexist and compete together.