Relationship between Shape of Slope and Speed Reduction Effect of Sinusoidal Hump

Abstract

In this study, we investigated the relationship between the shape, vertical acceleration and speed suppression effect of humps, which have been installed in various places in reference to the technical standards of the Ministry of Land, Infrastructure, Transport and Tourism. As a result, it was found that some of the cast-in-place asphalt humps were lower in height than the standard, and some of them had a small slope, which did not reproduce the shape of the sine wave, and had a small maximum slope. From the results of the speed survey, it was found that the smaller the uphill maximum gradient, the smaller the speed suppression effect during hump passage. According to the acceleration survey, the vertical acceleration of the backrest of the driver's seat tended to be smaller as the upward maximum gradient was smaller. It is considered that the discomfort caused by the vertical acceleration is reduced and the speed suppressing effect is not sufficiently exerted.