Security Screening Queues with Impatient Applicants: A New Model with A Case Study

Security screening policies are critical in military contexts, airports, ports, and visa issuance processes in order to minimize risks from terrorists, smugglers, fugitives, and others. However, such screening procedures also increase congestion and inconvenience for normal applicants, which may create a trade-off for the authorities balancing between risk and congestion. In this paper, we develop a game-theoretical model to investigate optimal screening policies that acknowledges the trade-offs between risk, congestion, and abandonment behavior of the applicants. To calculate the average waiting time in the screening queue with heterogeneous impatient applicants, we use a two-dimensional Markov chain model. As a case study, we tackle the security screening process of US visa applications by conducting an online survey. Collected data shows some key aspects of applicant preferences such as abandonment behavior. We conduct sensitivity analysis for our model. We show that if the authorities take the abandonment behavior of the applicants into account beforehand, they may achieve higher utility depending on the characteristics of applicants.