One of the headline objectives of the U.K. Highways Agency (HA) is to reduce congestion and improve road safety while undertaking necessary highway maintenance. To this end, HA has invested significant resources in developing an appropriate technology to collect road condition and structural data at traffic speeds. This is reflected in the recent procurement for HA of a prototype traffic-speed deflectometer (TSD). The machine, originally developed by Greenwood Engineering A/S of Denmark, exploits the Doppler effect by using lasers to measure pavement deflection velocities under the loaded wheel of a truck. As part of a research program at the U.K. Transport Research Laboratory, the TSD is being developed to undertake structural surveys at traffic speeds. This paper describes the operation of the TSD and continues with a discussion of one of the most challenging aspects of the research program: the development of a calibration procedure. The proposed procedure compares the response of a particular section of road to the TSD, as recorded by an accelerometer embedded in the road pavement, with that recorded by the Doppler lasers on the TSD.

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Track sub-structural stiffness is a major factor in the deterioration of track geometric quality as a result of the rail traffic that passes over it. Whilst track geometric quality has been measured at normal line speed for many years, determination of the condition of the substructure has only been possible at discrete locations using stationary devices or invasive manual inspection.This paper describes the problems caused by differential track system stiffness and progress with research that seeks to identify and implement a suitable technology that will enable the measurement of track structural stiffness at normal linespeed. Acquisition of this information on a production basis and use of it in conjunction with other condition data collected routinely offers Network Rail the opportunity to progress towards more effective targeting of track maintenance and renewal resources through greater knowledge of whole track system condition.