Buying road signs involves choosing between standardized regulatory signs and customized markers. Most professional-grade signs are constructed from heavy-duty aluminum (typically 63 or 80 mil thickness) and utilize 3M reflective sheeting to meet DOT and MUTCD standards . Standard Regulatory Signs
: Maximum visibility, 10x more reflective than standard materials.
A standard 18"x6" double-sided reflective sign for $33.16 at SafetySign.com .