This report describes the first stage in a programme of work that is being carried out by TRRL with the object of developing a machine for the routine measurement of the macro-texture of road surfaces. It gives an account of a system, using a contactless sensor mounted in a moving vehicle, that has been used to measure the texture-depth of substantial lengths of motorway M1. The main findings of the study were as follows: (1) the system is capable of continuous texture measurements at speeds of at least 35 km/h. (2) the coefficient of variation of the averages of measurements obtained for 20-metre sub-section lengths of road was estimated to be about 5 percent. (3) the system provides a ready means of assessing the texture of large road networks, and so will assist in the setting of specification limits as well as providing a means of checking compliance. (4) the approximately 200 km length of motorway studied was found to have half of its length with a sand-patch equivalent texture depth of above 1.3 mm and only just over one percent below 0.5 mm. (Author/publisher)
Abstract