R1-1 Stop Signs 24"x24" R1-1 Stop Signs 30"x30" R1-1 Stop Signs 36"x36" R1-1 Stop Signs Official MUTCD Signs meet current federal construction specifications for MUTCD Signs. Our traffic signs are constructed of rust-free,.080 heavy gauge, durable aluminum. These traffic signs are made using 3M Engineer Grade Prismatic(EP) reflective sheeting and 3M inks. 3M Engineer Grade Prismatic Reflective signs are rated by 3M for at least 7 years no-fade service. High intensity 3M sheeting is rated for 10 years no-fade service. Traffic signs have holes drilled at top and bottom center for easy mounting.