The slope-only condition (the running slope of the ramp) was included because it has been assumed to provide useful information for alignment, although this assumption has never been documented.
The participants completed eight trials per alignment cue, including two trials in which the cue was aligned with the ramp's running slope (0 degrees), and one trial each with the cue positioned 15, 30, and 45 degrees to the right and to the left of the running slope.
With the exception of the slope-only condition, the task for the participants was to base their heading on the alignment cue, not the ramp's running slope. We hypothesized that the greater the discrepancy between the two, the more heading error would occur.
This general pattern of results suggests that although slope alone is not a particularly useful alignment cue (as shown in Table 1), a running slope that is discrepant with an alignment cue by 30 degrees or more may have a deleterious effect on the usefulness of that cue.
The running slope is a measure of the slope parallel to the direction of circulation; the cross slope is measured perpendicular to the direction of circulation.
In this case, the running slope of the curb ramp, which is permitted to be up to 8.33 percent, is also the cross slope of the accessible route across curb ramp; cross slopes are not permitted to exceed 2 percent.
Depending on the site conditions, it may not always be possible to achieve compliant running slopes. For example, extremely hilly terrain may prevent developers from installing a route with a compliant running slope, but where a compliant route is achievable, it must be provided.
Minimum technical provisions for trails required to be accessible including surface, tread width, gap openings, protruding objects, changes in level, passing space, resting space, running slope, cross slope, and edge protection.
Specific exceptions were included for trail width, level changes, resting spaces, running slope, and cross slope.
Because curb ramps are likely to be present at crosswalks and their slopes are often not aligned with the direction of the crosswalks (see Scott et al., 2011), the running slope of the ramp and the cues were sometimes aligned in the same direction and sometimes in conflicting directions.
The participants completed five trials per alignment cue: one trial in which the cue was aligned with the running slope of the ramp (0 degrees) and one trial each with the cue (the simulated crosswalk) positioned 10 degrees and 20 degrees to the right and to the left of the running slope.
-- The curb cut from the parking lot to enter the building has running slopes
that exceed the maximum allowed.