A method, implemented in an electronic processing system that includes a memory and one or more processors, includes receiving, at the electronic processing system, sensor data representing information collected by a sensor (i) located on or in a first vehicle and (ii) configured to sense an environment external to the first vehicle, storing the received sensor data in the memory, and determining, via the one or more processors and based on the stored sensor data, an identifying characteristic of a second vehicle different than the first vehicle.