Incheon Subway Line 1 Songdo Section 8 extension route map. Incheon City's cost-benefit (B/C) ratio is only 0.3. Park Chan-dae says, "We will take responsibility and normalize it." It has been found that the Incheon Subway Line 1 Songdo Section 8 extension is not economically feasible. Incheon Mayor-elect Park Chan-dae's transition committee said that Incheon City and the Korea Development Institute (KDI) will agree on the cost ratio as a result of the first preliminary feasibility review meeting for the 'Incheon Subway Line 1 Songdo Section 8 Extension Project'. Benefits (B/···