A driving intention estimation, driver assistance and vehicle with the driver assistance for providing a stable estimation of a driver's driving intention even if detection of a relationship between an own vehicle and lane markers is lost. A plurality of imaginary drivers of a first type and a second type, each being given a respective driving intention, are provided. When detection of lane markers is reliably kept, a driving intention by a real driver is estimated based on a comparison between an operation of the real driver to operations of the imaginary drivers of the first type that are calculated based on the relative positional relationship of the own vehicle to the detected lane marker. When the detection of lane markers is lost, operations of the plurality of imaginary drivers are calculated based on the relative positional relationship of the own vehicle to a preceding vehicle. In response to the status of detection of the lane marker, either the imaginary drivers of the first type or the second type are selected.