国土 こくど開発 かいはつ幹線 かんせん自動 じどう しゃ どうであれば
kokudokaihatsukansenjidōsha dōdeareba

Noun
Da Copula

The "-eba" conditional form ("if/when…") of 国土開発幹線自動車道

1. If it were a national highway trunk road development…; If the national highway trunk road development existed…

Ba Conditional