横おう断だん地ち下か道どう

Meanings

1

noun

underpass; underground crossing

A pedestrian tunnel or passageway that goes under a road or railway, allowing people to cross safely.

below, down, descend

道road-way, street, district

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).