Section 1102 requires that all accessible areas of buildings be connected by accessible routes. Outdoor accessible routes include accessible parking spaces, passenger loading zones, public right-of-way, and building entries. Indoor accessible routes connect accessible areas within buildings. Accessible routes must have firm, stable, slip-resistant surfaces. Changes in level must be accommodated with ramps for slopes exceeding 1:20 (5 percent). Curb cuts provide accessible transitions from sidewalks to roads. Door openings in accessible routes must have minimum 36-inch clear width and lever-operated handles. Corridors and hallways must be minimum 36 inches wide for single passage or 48 inches for two-way traffic. Handrails must be installed on stairs and ramps in accessible routes.