A DEVICE TO MEASURE THE TRANSVERSE POSITION OF A VEHICLE IN A TRAFFIC STREAM --14TH ARRB CONFERENCE, 28 AUGUST - 2 SEPTEMBER, 1988, CANBERRA, ACT, AUSTRALIA; PROC. PARTS 1 - 8

Arrb has developed a device known as the transverse position indicator (tpi) which allows the location of the edge of a tyre with respect to a fixed reference point to be accurately determined. Also, two tpi's can be set up in such a way that the width of a single tyre, or a dual tyre assembly, can also be measured. The purpose of this paper is to describe the device and to report the results of field and laboratory evaluations set up to determine its accuracy and its durability. The tpi can be conservatively expected to predict transverse position, for a range of vehicle types, loads, tyre pressures and speeds, to an accuracy of plus or minus 5 mm, though higher accuracies can be expected on most occasions. The durability of the tpi's was satisfactory, with accurate results still being obtained after the devices had been trafficked by 10,000 axle pairs. The devices, when used in pairs, could easily discriminate between conventional single tyres, wide single tyres, and dual tyres (a). For the covering record of the conference, see IRRD no 808936.