2010 ADA Standards for Accessible Design Pocket Guide
802.2.2.1 Lines of Sight Over Heads.
Where standing spectators are provided lines of sight over the heads of spectators standing in the first row in front of their seats, spectators seated in wheelchair spaces shall be afforded lines of sight over the heads of standing spectators in the first row in front of wheelchair spaces. [S.H. 4.33.3]