2010 ADA Standards for Accessible Design Pocket Guide

407.2.3.2 Car Designations.

Destination-oriented elevators shall provide tactile car identification complying with 703.2 on both jambs of the hoistway immediately below the floor designation. Car designations shall be provided in both tactile characters and braille. Tactile characters shall be 2 inches (51 mm) high minimum.

Figure 407.2.3.2 Car Designations on Jambs of Destination-Oriented Elevator Hoistway Entrances