If you’re only looking for daytime visibility, standard non-reflective aluminum signs would work well. Reflective signs are a step forward because they offer great visibility at night too. Reflective Posted signs for property come in three grades - Engineer Grade, High Intensity, and Diamond Grade. However, the best reflectivity comes from fluorescent posted signs which combine the high conspicuity of fluorescent colors with great nighttime reflectivity as well as wide-angle performance of 3M micro prismatic lens technology.