Underpass 1 : (1) A grade separation where the subject carriageway passes under an intersecting carriageway or railway (see grade separation and overpass). (2) A tunnel constructed for the use of pedestrians, cyclists and/or stock
Peter Milne and Kieran Sharp, ARRB Group, and Bob Ungers, consultant, Austroads Glossary of Terms (4th Ed.), Austroads Ltd., Sydney, NSW, Australia 2010. http://www.bicyclensw.org.au/files/u1/Austroads_Gl ossary_of_Terms_4th_edition.pdf (Road Trfc and Transp Sfty - Brit) {529}