What colour and shape are guide signs on interstate highways?

GUIDE SIGN COLOUR CODING: GREEN: Interstate highway directional signs — destinations, distances, exit numbers; BLUE: Services information (gas, food, hospital, lodging); BROWN: Recreational areas, national parks, historic sites; WHITE: Local regulatory signs (speed limits) and street name signs; YELLOW: Warning signs. GREEN EXIT SIGNS: EXIT NUMBER in upper right corner; destinations listed in order of distance; advance signs appear 1 mile and 1/2 mile before the exit; the exit ramp sign appears at the exit itself. UNDERSTANDING EXIT SIGNS: 'Exit 45 A-B' indicates a split exit; 'Exit 45 Next RIGHT' or arrow indicates which lane to be in; numbers reflect milepost positions in most states (Exit 45 is near mile marker 45 on that highway).