Development of a Smart Retroreflective Particle a "Tetra-Chip" to be used as a Substitute for "Drop-On" Road Beads

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Accurate and dependable positioning of vehicles is essential for automated and autonomous vehicles and lateral positioning is especially important. Just think of a thirty ton driverless lorry drifting into the wrong lane.During the transition from having only human drivers to a mixed fleet ie. Vehicles with human drivers only, automated vehicles with human drivers and fully autonomous CAVs on the roads. The road network will have to be properly prepared so that both humans and machines can read road-markings in order to make the correct decisions. Part of how this will be achieved is to ensure that lane markings can be read by both humans and machines.Detection of lane markings at night is achieved by the retroreflection of a vehicle headlight back to the driver of the vehicle, or a sensor, in a machine driven vehicle. This retroreflection is facilitated by exposing tiny glass beads embedded in the road-marking paint. The exposition of these tiny glass beads occurs as a consequence of the abrasive effect of vehicle roadwheels on the road-markings, so it is essentially a system. However, for the system to be functioning as it should, takes time and obviously immediate retroreflection is required for the prevention of accidents. Accordingly, in order to resolve this issue, when new markings are laid down, they are surface-dressed with "drop-on" road beads. Unfortunately a significant proportion of these "drop-on" road beads are lost in the first few days, due to the abrasive effect of vehicle roadwheels, and/or by being blown/washed away by inclement weather due to poor adhesion. This is wasteful in a "green" sense and contributes to global warming,because the manufacture of road beads is energy inefficient. It is also wasteful in an economic/commercial sense and reduces the effectiveness of the road-markings contribution to accident prevention.Another issue affecting standard and "drop-on" road beads is that they do not retroreflect at night in wet/rainy conditions (when they are most needed), due to a film of water covering the glass beads which alters their refractive index and reflection becomes specular rather than retro.Seeward Ltd has developed a Smart retroreflective particle designed to address all these issues and has the potential to be used as a substitute for "drop-on" road-beads. The aim of this this project is to test the performance of the particle under laboratory conditions prior to licensing the technology for commercial manufacture.