GC-Series Guidance Direction GC1: Pre-advance Exit Direction GC2U: Advance Exit Direction GC2D: Advance Exit Direction GC3U: Supplementary Advance Exit / Through Direction GC3D: Advance Exit Direction GC4U: Exit Direction GC4D: Exit Direction GC5U: Off-ramp Direction GC6U: Off-ramp Direction GC7U: Road Exit Direction GC8U: Road Advance Exit / Through Direction