Reference is made to methods used to measure the lateral position of vehicles on the road - observation, photography, contact sensors, video cameras and restrictions on the use of such methods discussed. This article is concerned with equipment designed to overcome such problems, and is of particular interest when it is required to obtain data on a number of passing vehicles in particular locations of a road network. It is described as being fully-automated, portable and simple, and with low operating costs. Diagrams are used to illustrate the system design whereby four infrared photocells are set over the road, two parallel and the other two at a known angle with respect to the others so that the beams are cut off by the tires of the vehicles. Four reflectors on the other side of the road reflect the beams backwards. The velocity of a vehicle is calculated from the time which a vehicle spends between the two parallel beams, and the lateral position from the other two time intervals between offsets of photocells. Equations for computing the data are presented, and the microcomputer used to measure time intervals between offsets of beams and to calculate speed and lateral distance from the reference point of each passing vehicle described. The use of this system - for the first time - in a Finnish research project is described, whereby vehicle position distribution was used in a study concerned with the spread of traffic across pavement width and associated pavement deformation. The results of this study are presented graphically and the implications discussed. /TRRL/

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  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • SUMMALA, H
    • Merisalo, A
  • Publication Date: 1978-7

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Filing Info

  • Accession Number: 00189214
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Apr 12 1979 12:00AM