Green signs on highways typically indicate:

Green is the color of guide signs that show direction, distance, and destination information on highways. Examples: 'Exit 47 — Springfield 1 mile', 'I-80 West — Cheyenne 220', 'Junction US-50'. The green-and-white color scheme is standardized so drivers can identify navigation information at a glance, separate from warnings (yellow), regulatory signs (white), construction (orange), and service signs (blue or brown). Mile markers on interstates are also green. Reading green signs in advance lets drivers plan lane changes and exits without last-minute maneuvers. Cities and major destinations are listed alongside route numbers so drivers can find their way even if they do not know the route number system.