A server of an information processing system receives, from each of the vehicles, a signal detection location where a traffic signal is detected by an imaging unit of each of the vehicles, and travel information at the signal detection location, calculates, based on the information from each of the vehicles, a mean distance L from the signal detection location to the traffic signal, and a mean speed S at the signal detection location, and evaluate a risk of the traffic signal based on at least the mean distance L and the mean speed S. The server then provides attention information to the vehicle approaching the traffic signal having the risk higher than a prescribed value.