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.
135--the result of a linear trend of larger errors with greater angles of misalignment between the running slope of the ramp and the cue: F(1, 19) = 4.
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.
Not only was the running slope of the ramp found to be an inaccurate alignment cue, but it was found to interfere with the usefulness of the other cues when it was misaligned with those cues by 30 and 45 degrees.
In principle, alignment based on the perception of a running slope requires discriminating differences between the downward angle and the lateral forces on the body when walking or standing facing various directions relative to the running slope of the ramp.
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.
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.
Clearly, an excessive counter slope of the gutter makes it difficult for a person in a wheelchair to maintain the momentum needed to move across the slope of the gutter and onto the running slope of the curb ramp.
It is not uncommon to find accessible routes with running slopes more than double the maximum permitted.