Heart rate as a measure in road layout design.

Abstract

It is known that stress, both psychological and physical, along with other factors, increases the heart rate. Making the assumption that a poor road junction design gives rise to greater stress than a good design, experiments have been carried out to determine whether driver heart rate changes can be used as a measure of the stress induced by various road junction designs. Statistically significant differences in average heart rates were obtained for different parts of motorway interchanges, the order being as expected from a subjective estimate of their difficulty. However, a comparison of corresponding parts of different interchanges did not lead to significant differences. It is believed that this was only through lack of a sufficient number of results and that the method would be sensitive enough if more results were obtained. A second part of the work investigated instantaneous heart rate rises. It was found that considerable care must be taken in interpreting such changes since very often the control movements required at a junction, involve sufficient physical effort to produce heart rate changes of the same order as those produced by psychological stress.