Groove 1 : Narrow depression or rut in what is otherwise a relatively flat and smooth riding surface, which could catch a bicycle wheel where it is parallel to the direction of travel
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}