One important use case for Vehicular Ad-hoc Networks (VANETs) are applications related to emergency vehicles (EV). V2I (Vehicle-to-Infrastructure) communication can provide the infrastructure and protocol stack necessary to establish a communication channel between the transceivers in the EVs and the ones in the traffic lights, reducing accident risks and also help save valuable time. This paper outlines the system design of an EV warning system that makes use of V2I communication. A prototype of the system has been tested in a traffic simulation environment including EVs and traffic lights. To evaluate the system we performed a simulation and conducted a performance comparison between the travel times for EVs in normal traffic and when the system is in use. © 2020 IFIP.