Honolulu International Airport has designated areas where taxis may pick up customers.
These are the areas outside the Baggage Claims on Level 1 (click image for larger version):
Illustrated maps for Bag Claim level pick-up areas:
Bag Claims 6-11: Pre-Arranged Area 1
Bag Claims 16-21: International Garage
Bag Claims 22-31: Pre-Arranged Area 5
International Arrivals: International Garage