Date: 201203
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: IMC
Weather elements / visibility: Fog; 1.5
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Final Approach
ATC / advisory: Tower ZZZ
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Developmental
Human factors: Human-Machine Interface; Situational Awareness
Second reporter function: Supervisor / CIC
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Critical
Detector: Automation Air Traffic Control
Result: Air Traffic Control Issued New Clearance
Contributing factors: ATC Equipment / Nav Facility / Buildings; Human Factors; Procedure
Primary problem: Procedure

Narrative: I was working Local West (arrivals) to Runway XXR when I noticed a target on the ASDE-X. We tend to get erroneous targets periodically and expected it to go off. When it didn't; Air Carrier X was short final (100 FT) and I sent the aircraft around with the advisory of a 'target' on the ASDE-X. The weather was 400 OVC; 1 ½ miles visibility. Fog obscured the first half of the runway so I wasn't able to visually see the vehicle out the window. After issuing the go around; Local East advised he had a vehicle in sight. We watched in horror as the out of control vehicle continued down Runway XXR; through the grass onto Taxiway Sierra; crossed Runway YY; and entered Runway XXL. By this time; we had shut the airport down. The airport vehicle and police intercepted the vehicle at the approach end of Runway XXL and apprehended the intoxicated driver. We had about 10 aircraft in the hold and approximately 15 aircraft waiting for departure. The ASDE-X never went off because the vehicle was traveling the same direction and didn't recognize a conflict.


Second narrative: I was the FLM in the Tower at the time of the occurrence. A vehicle appeared on Runway XXR in front of landing traffic. The traffic was sent around and subsequent arrivals were put into holding patterns. I directed the TRACON FLM to stop all inbounds and Tower Controllers to stop all aircraft movement until the vehicle was stopped. The vehicle proceeded down the full length of Runway XXR; crossed over the approach end of another runway; then proceeded down the full length of Runway XXL.  The vehicle was initially detected by ASDE-X and the Controller working Local Control. Police units were dispatched immediately and gave chase to the vehicle until it stopped. Visibility was poor as the field was blanketed with fog. Recommendation; two items come to mind regarding this event. ASDE-X notification and no set procedures to handle this type of safety threat. First; I feel a modification to the ASDE-X safety logic to alert controllers of runway intruders needs to be addressed. Our controllers 'tag-up' vehicles that are given permission to enter the runways. Perhaps ASDE-X could be enhanced to alert controllers to untagged targets that enter the runway (WARNING: RUNWAY XXR INTRUDER; etc). In this situation; seconds mattered. An intruder alert feature would enable the Controller to react more quickly to the safety threat. Secondly; all of our emergency services are geared towards aircraft emergencies. There are really no procedures in place that address a security breach that affects aircraft safety. I made a recommendation to our facility management team that new airport alert codes and procedures be implemented to better address situations like this one. Perhaps this should be addressed nationally through out the facilities providing ATC services.


Synopsis: Tower Controller described an unauthorized runway entry event resulting in a directed go around. The reporter questioned the functionality of the ASDE-X equipment.