Abstract: A payload monitoring system is disclosed for use with a haul vehicle. The payload monitoring system may have at least one emitter configured to direct an energy beam into the haul vehicle during relative movement between the at least one emitter and the haul vehicle, and at least one receiver configured to detect the energy beam and to generate a corresponding signal. The payload monitoring system may also have a controller in communication with the at least one receiver and configured to determine a loading condition of the haul vehicle based on the corresponding signal.