Safety and Geometric Aspects of Humps and Road Crossings

A speed hump is a local rising of a public road, formed as a sinusoidal, and meant to force drivers physically to decrease their speed. A plateau is also meant to moderate the speed, but this is a flat rising with gradual slopes. Because of the large diversity in legally normalized construction types, the geometric control of these raised constructions is a complex matter. Moreover, because of the typical low to the ground form of a flatbed truck, problems arise when the road crossings shows a round form. The objective of this study is to find a surveying method to collect geometric data, in order to inspect speed humps, plateaus and road crossings. Depending on the categorisation of the different sorts of roads, and the construction principles for flatbed trucks, the work also deals with the theoretical definition of the possibility of passing the road crossings with flatbed trucks. The problem is extrapolated to several successive obstacles and is also applied on traffic thresholds and traffic plateaus, which are also considered as obstacles for flatbed trucks. The paper discusses a surveying and processing method in design, which makes use of a surveyor's level and proposes the development of new surveying methods namely an adapted method for a level, a method for a total station and a method for a GPS instrument. Finally, the results of an interesting comparison between the different methods by means of surveys on site are presented and the results are applied on some practical examples.