Abstract: This study presents a road-marking concept that integrates slim passive radar reflectors to give autonomous vehicles a dependable lane reference when optical sensors fail. Aluminium resonant profiles are cast between a cold-plastic wearing layer and an acrylic resin underlay, yielding a high radar cross section at shallow grazing angles while keeping luminance and skid resistance within current road standards. Laboratory trials covered radar performance and durability. Geometry strongly influenced the radar response: the best shape delivered a signal-to-noise ratio above ten decibels at a range of five metres. Durability to wear was assessed with the Aachener Raveling Tester; after six hundred tyre roll-overs the marking retained full adhesion and reflectivity, which made it adequate for road use. These findings confirm that radar-enhanced markings can be produced with ordinary materials and equipment, offering a practical route to reliable lane detection and safer autonomous driving in poor weather.