横おう断だん地ち下か道どう

• 地ち下か道どう

  地下道 is a general underground passageway, while 横断地下道 specifically refers to one used for crossing a road or railway.

• 横おう断だん歩ほ道どう

  横断歩道 is a pedestrian crossing at street level, whereas 横断地下道 is an underground crossing.

Compound of 横断 (crossing) + 地下道 (underground passage).