Diamond Grade Type XI Vs. HIP Sheeting for Highway Safety Diamond Grade Type XI and HIP reflective sheeting serve different traffic-safety needs. HIP provides strong performance and cost efficiency for municipal roads, parking areas, factory sites, local streets, and standard traffic signs. Diamond Grade Type XI offers greater brightness and wide-angle visibility for highways, toll plazas, overhead signs, interchanges, sharp curves, and complex nighttime driving environments. The best choice depends on traffic speed, sign placement, viewing angle, road risk, maintenance requirements, and total long-term project cost.