Abstract: There is described a method of estimating one or more properties of traffic passing along segments of a road network, the traffic comprising a plurality of vehicles. The method comprises receiving, from a radio navigation receiver located at each vehicle of a subset of the vehicles, one or more first properties of each of those vehicles. The method also comprises using distributed acoustic sensing to generate, as a function of time and of position along a subset of the segments of the road network, signals representing acoustic vibration caused by the traffic at one or more sensing optical fibres that extend along the subset of segments.

Abstract: In a printed article, pigment flakes are magnetically aligned so as to form curved patterns in a plurality of cross-sections normal a continuous imaginary line, wherein radii of the curved patterns increase along the imaginary line from the first point to the second point. When light is incident upon the aligned pigment flakes from a light source, light reflected from the aligned pattern forms a bright image which appears to gradually change its shape and move from one side of the continuous imaginary line to another side of the continuous imaginary line when the substrate is tilted with respect to the light source.