In 1995, there were basic plans for five subway lines within Daejeon spread over 100 km of track.

[1] While Daejeon Metro Line 1 started construction in 1996, Line 2 has gone through a number of changes and proposals over the years, including making it a maglev modeled after the maglev in the National Science Museum.

[2] The maglev design passed a feasibility study in 2012,[3][4] but two years later it was announced the new line would be a streetcar tram system.

[6] In 2017, the maglev feasibility plan officially expired, which officially ended plans for the line to be a maglev unless a new feasibility study would be conducted.

[7] In 2018, the Korea Development Institute (KDI) began a new feasibility study, this time for the proposed tram[8] but was exempted along with 22 other projects as part of the 2019 Balanced National Development Project[9] before passing KDI's review in August 2019.