In an information processing system, a regulation recognizer recognizes regulatory information displayed on a first indicator disposed external to a subject vehicle from a captured image. A condition recognizer recognizes conditional information displayed on a second indicator disposed external to the vehicle from the captured image. The conditional information is indicative of a condition under which the regulation indicated by the regulatory information recognized by the regulation recognizer is to be applied, where the condition is an environmental condition about an environment around the vehicle. An output controller controls outputs generated by an output generator. If the environment around the vehicle recognized by the environment recognizer satisfies the environmental condition indicated by the conditional information recognized by the condition recognizer, the output controller controls the output generator based on the regulatory information recognized by the regulation recognizer.