Moving Lifelines: Fixed Sites or Mobile Fleets for Emergency Medical Device Delivery?

Timely use of an automated external defibrillator (AED) is critical for out-of-hospital cardiac arrest survival. Traditional static systems require a nearby community responder to retrieve an AED from a fixed location before reaching the patient, whereas emerging mobile systems place AEDs on taxis or ride-hailing vehicles for direct delivery by participating drivers. We study how cities should allocate a limited AED budget between these systems to maximize timely AED deliveries.

We develop a stochastic spatial model where static delivery requires a two-leg responder-AED-patient trip, whereas mobile delivery pre-couples AED and responder but is constrained by fleet idleness. We show that static system performance depends jointly on AED and responder density: increasing either resource eventually yields a performance ceiling determined by the other. Mobile deployment avoids this bottleneck but discounts each equipped AED by fleet availability. Cities with different population levels may therefore favor different systems, and the preferred system can switch from mobile to static as population grows. Our analysis provides parsimonious policy prescriptions: optimal policies typically concentrate AEDs in one channel, and computable thresholds identify when static, mobile, or hybrid deployment is optimal. Calibrating our model with over 10 datasets, we find static deployment favored in New York City and mobile deployment in Singapore.

Authors: Zeyu Lin (University of Toronto, Rotman School of Management), Weiliang Liu (The Chinese University of Hong Kong), Jingwei Zhang (Cornell University, SC Johnson College of Business)

Status: Working paper, available at SSRN

Recommended citation: Zeyu Lin, W. Liu, and J. Zhang. (2026). "Moving Lifelines: Fixed Sites or Mobile Fleets for Emergency Medical Device Delivery?" Available at SSRN: https://ssrn.com/abstract=7119321.
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