ADAAG Manual

Platform Edges

The detectable warning must be placed at the platform edge and extend the full platform length in a 24 inch depth. This depth is an absolute dimension, not a minimum. Some platforms are edged with a buffer material that is designed to break away if hit by cargo trains. This material extends beyond the normal vehicle envelope. Where this breakaway material is installed at a platform edge, the width of the detectable warning surface can begin at the edge of the breakaway material rather than at the edge of the platform; otherwise, the detectable warning must extend to the edge of the platform. Since the sway of some rail cars may overlap a platform edge, the area of the detectable warning installation should not be considered a safety zone but rather an indication of an adjacent drop-off or platform edge. Where there is no specific edge to a vehicle boarding area, the detectable warning should be placed at the boundary of the vehicle dynamic envelope.