In general, the invention is directed to monitoring fluid retention that may accompany congestive heart failure and pulmonary edema. The motor vehicle comprises a body provided with seats and a convertible roof, consisting of a front section adjacent to a windscreen frame and a rear section, which is pivotally connected to the rear part of the vehicle. When the test yields a desired result, the bone body is exposed to a second processing solution that is less acidic than the first, thus minimizing the exposure of the bone body to the harsh acidic conditions of the demineralization phase of the process. The invention is characterized in that liquid-impermeable portions are arranged at separate places in the article along sections of overlapping parts of the wicking layer and the liquid storage region in order to prevent the transfer of liquid over said parts from the wicking layer to the storage region. The steering characteristics are determined in response to running conditions.