A serious injury was sustained by a tug driver following a collision with the left wing of Air Wisconsin flight 6181, a CRJ-200, during taxi operations at Chicago O’Hare International Airport (ORD). No injuries were reported among the airplane’s crew or passengers. Night visual meteorological conditions (VMC) prevailed at the time of the accident. Flight 6181 landed at ORD and was initially held at the B Pad for an open gate (see Figure 1). Once cleared, the aircraft proceeded southbound on Taxiway A under a standard clearance. The first officer was actively monitoring both ramp and ground control frequencies during the taxi. The captain reported first observing the tug on Taxiway B as the tug began crossing at the access road. The tug appeared to be slowing down suggesting an intent to stop. The captain could not recall whether the tug’s headlights were illuminated and believed he saw the vehicle using ambient lighting. After briefly diverting attention toward the gate area, the captain looked back and recognized an imminent collision with the tug. Braking was initiated immediately by the captain, but the impact occurred shortly thereafter. The captain described the impact as “not that bad” and believed the tug had struck the wingtip. The flight crew then communicated with the flight attendants, followed by dispatch via the Aircraft Communications Addressing and Reporting System (ACARS). According to the tug driver, while returning from the international terminal, the vehicle approached the service road leading to the L gates. Before entering the road and crossing taxiway B, the tug came to a complete stop at the designated stop sign and the driver observed an airplane taxiing outbound on Taxiway B. The driver checked both directions and waited until the outbound aircraft cleared the taxiway. The driver also verified that no aircraft were approaching from behind or the opposite direction before proceeding to cross the taxiways (A&B). The driver stated that as the tug was crossing the taxiways, the left wing of flight 6181, approaching on taxiway A, was not visible until the last moment, leaving insufficient time to react. He also noted the absence of a nose-gear light on flight 6181, which may have contributed to the tug driver not detecting the presence of flight 6181 before the collision. Figure 1. Ground position tracks for flight 6181 with respect to taxiways A & B. The collision resulted in the tug overturning and trapping the driver, leading to serious injury. Post-flight inspection revealed substantial damage to the leading-edge front spar of the airplane’s left wing. The tug driver emphasized that had he been aware of the airplane’s presence, he would not have entered the intersection. Figure 2. Damage to the aircraft (Source FAA). Figure 3. Damage to the tug (Source FAA). According to the Chicago Department of Aviation (CDA) ground motor vehicle operating regulations manual, dated August 2023, a driver must stop prior to initiating the crossing of the taxiways A, B, and V to determine if the crossing could be accomplished without stopping in the islands between the taxiways. Vehicles on service roads must yield to vehicles crossing taxiways.