Understanding congestion in airport surface operations using 3D fundamental diagrams

• Developed a 3D fundamental diagram to analyse the efficiency of airport surface operations. • First causal modelling framework to understand how technology drives airport surface congestion. • Developed two novel metrics to characterize airport surface operational efficiency. • Validate approach using a unique day-to-day operation data of five airports. • Results are relevant in airport benchmarking, planning, and management. Operational delays that arise when demand on the airport surface app