Field test of on-board diagnostics (OBD) use during periodic emission testing for Euro 5+ motorcycles. Fifty-three Euro 5+ motorcycles were tested to examine feasibility and practicability of OBD-based inspection procedures. All motorcycles had 6-pin or 16-pin connectors. Challenges included locating OBD ports, accessing them with mechanical tools, engine coolant temperature readouts for oil/air-cooled motors, revving to 2500 rpm on some scooters, and measuring lambda with short exhaust systems. OBD information improves periodic technical inspection reliability for Euro 5+ motorcycles.