Page 20 of the Rice Signs 2017 Traffic Safety Catalog begins the Warning Signs section with general specifications for diamond-shaped yellow warning signs (0.080 aluminum substrate, rolled edges, Engineer Grade or HIP reflective sheeting with 6, 7.5, or 10-year warranties in standard sizes from 24 by 24 inches up to 48 by 48 inches), followed by the W1 series Horizontal Alignment Signs. These signs alert drivers to upcoming turns, curves, and changes in road alignment: W1-1 Turn signs for sharp turns, W1-2 Curve signs for gradual curves, W1-3 Reverse Turn for two consecutive turns, W1-4 Combination Curve / Reverse Curve direction change signs, W1-5 Winding Road for three or more curves, W1-6 Large Arrow signs at apex, W1-7 Two-Direction Arrow for T-intersections, and W1-8 Chevron Alignment Signs for marking the inside of a curve.