Enhancing Surface Safety: A Guide to Vehicle Movement Area Transponders (VMATs)

The FAA and the aviation community are pursuing a goal of zero serious close calls on the airfield. Identified in the February 2023 Safety Call to Action Initiative, this goal includes mitigating incursions from both aircraft and ground vehicles.

To help eliminate these accidents, airport operators can equip vehicles that traverse airfield movement areas with Vehicle Movement Area Transponders (VMATs).  VMATs send precise vehicle location and callsign information to the surface surveillance systems installed in towers, which help air traffic controllers to safely manage aircraft and vehicle traffic on the airport surface. Detailed information is available in Advisory Circular 150/5220-26 and CertAlert 25-01.

What Are VMATs and How Do They Work?

VMATs are specialized Automatic Dependent Surveillance-Broadcast (ADS-B) units installed directly on airport ground vehicles.

  • Safety Objective: VMATs reduce risk on runway, taxiway, and apron movement areas at airports with surface surveillance systems.
  • Technology & Function: VMATs utilize ADS-B technology to broadcast a vehicle's exact position. This allows ATC and pilots to see vehicle locations on dedicated surface displays.
  • Transmission Details: Operating typically on the 978 MHz/UAT link, these units transmit highly precise GPS coordinates to ATC and nearby aircraft.

Airfield Surveillance Systems

VMATs integrate seamlessly with advanced airport surface surveillance infrastructure to display the position and call sign of equipped vehicles and aircraft directly in the ATC tower.

  • ASDE-X and ASSC: Airport Surface Display Equipment, Model X (ASDE-X) and Airport Surface Surveillance Capability (ASSC) are powerful surveillance systems currently utilized to monitor airfield movements and enhance safety. These are actively in-use at 44 busy U.S. airports in the National Airspace System (NAS).
  • Surface Awareness Initiative (SAI): Following the Safety Call to Action, the FAA established the Surface Awareness Initiative (SAI) to provide supplemental situational awareness for controllers at FAA Towers without existing ASDE-X or ASSC capabilities. Similar to ASDE-X and ASSC, SAI systems use ADS-B to track aircraft and vehicles on the airport surface. At airports equipped with SAI systems, the position and call sign of aircraft equipped with ADS-B and vehicles equipped with VMATs are shown on surface displays in the air traffic control tower.  The FAA has installed or plans to install SAI at 220 airports through 2028, which will complete the installation of surface surveillance systems at all airports with FAA-operated towers.  In addition, the FAA is installing VMATs on all FAA vehicles operating at these airports. 

Guidance and Funding for Airport Operators

As highlighted in CertAlert 25-01, the FAA strongly encourages airport operators to take proactive steps regarding VMAT implementation.

  • Assessment: Airports should assess how VMAT equipment can improve surface safety and enhance situational awareness.
  • Equipping the Fleet: Airports that have ASDE-X, ASSC, or SAI systems (installed or confirmed to be installed) should equip their vehicles with VMATs and encourage the use of VMATs on other vehicles operating in the movement area. 
  • Funding Opportunities: The Airport Improvement Program provides federal grant eligibility and justification guidance for the acquisition and installation of VMATs (also known as squitters). This funding eligibility applies to airports equipped with ASDE-X, ASSC, and SAI systems.
  • Next Steps: Specific programmatic guidance detailing funding limits and rules can be found in PGL No. 24-01. The FAA encourages airports to work closely with their Airport District Offices to explore funding for these safety systems. The FAA is setting aside sufficient funding to fully equip airport-owned ground vehicles with VMATs, up to statutory limits on the federal share.

Related Information

Last updated: Wednesday, May 13, 2026