State estimation and response to active school vehicles in a self-driving system

This document discloses system, method, and computer program product embodiments for anticipating an imminent state of a school transportation vehicle. For example, the method includes receiving sensor data of an environment near an autonomous vehicle. The method further includes, in response to the sensor data including a representation of a school transportation vehicle, analyzing the sensor data to estimate, from a set of candidate states, a current state of the school transportation vehicle, wherein the candidate states include an actively loading or unloading state, an imminently loading or unloading state, and an inactive state. The method further includes, in response to the estimated current state being either the actively loading or unloading state or the imminently loading or unloading state, causing the autonomous vehicle to slow or stop until the school transportation vehicle is in the inactive state.