Dimensional Tolerances in Construction and for Surface Accessibility

1.1.7 Measurement of parking areas. Only accessible access aisles and passenger loading zones that are part of a larger parking area need to be measured. These areas should be considered as a pedestrian walk with a minimum width of 60 in. and a length of approximately 20 ft and with an ADA/ABA - AG maximum slope of 1:48 in both directions. Overall running slope (in the long dimension) and cross slope (in the short direction) should be measured according to Section 1.1.3 and 1.1.4. This means that the overall slope in the long dimension should be measured along the center of the aisle or zone using the ends of the area as elevation measuring points and cross slope should be measured at each end of the area and at the midpoint of the area. See Fig. 3.