A combination of a material-transferring vehicle, a material-receiving vehicle and a system for managing the transfer of material from the material-transferring vehicle to the material-receiving vehicle, wherein: the material-transferring vehicle comprises a first storage container and an unloading chute extending above or from a side of the first storage container, the unloading chute adapted to transfer material from the first storage container to the material-receiving vehicle alongside the material-transferring vehicle; an image sensor is mounted on the material-transferring vehicle or the first storage container for estimating a lateral separation distance between the first storage container and the material-receiving vehicle for receiving the material; a location-determining receiver is located at the material-transferring vehicle and adapted to estimate position data for guiding the material-transferring vehicle; and the system for managing the transfer of material from the material-transferring vehicle to the material-receiving vehicle comprises an electronic data processing system for guiding the material-transferring vehicle based on the estimated position data; characterized in that the image sensor comprises a camera, a stereo image sensor, or a monocular image sensor to determine the lateral separation distance between the material-transferring vehicle and the material receiving vehicle by identification of a reflective alignment pattern on the material receiving vehicle and estimation of the distance between the material transferring vehicle and the material receiving vehicle by identifying the vertical height of the reflective alignment pattern with respect to a reference vertical height at a known reference position, and that the electronic data processing system is configured for guiding the material-transferring vehicle based on the estimated position data and the estimated lateral separation distance, where the estimated lateral separation distance of the image sensor supersedes or augments the estimated position data for the material-transferring vehicle to maintain at least a minimum target lateral separation distance between the material-transferring vehicle and material-receiving vehicle during the transfer of the material. the material-transferring vehicle comprises a first storage container and an unloading chute extending above or from a side of the first storage container, the unloading chute adapted to transfer material from the first storage container to the material-receiving vehicle alongside the material-transferring vehicle; an image sensor is mounted on the material-transferring vehicle or the first storage container for estimating a lateral separation distance between the first storage container and the material-receiving vehicle for receiving the material; a location-determining receiver is located at the material-transferring vehicle and adapted to estimate position data for guiding the material-transferring vehicle; and the system for managing the transfer of material from the material-transferring vehicle to the material-receiving vehicle comprises an electronic data processing system for guiding the material-transferring vehicle based on the estimated position data; characterized in that the image sensor comprises a camera, a stereo image sensor, or a monocular image sensor to determine the lateral separation distance between the material-transferring vehicle and the material receiving vehicle by identification of a reflective alignment pattern on the material receiving vehicle and estimation of the distance between the material transferring vehicle and the material receiving vehicle by identifying the vertical height of the reflective alignment pattern with respect to a reference vertical height at a known reference position, and that the electronic data processing system is configured for guiding the material-transferring vehicle based on the estimated position data and the estimated lateral separation distance, where the estimated lateral separation distance of the image sensor supersedes or augments the estimated position data for the material-transferring vehicle to maintain at least a minimum target lateral separation distance between the material-transferring vehicle and material-receiving vehicle during the transfer of the material.