Methods and systems for training a parked vehicle detector. Video data regarding one or more parking sites can be captured. Positive training samples can then be collected from the video data based on a combination of one or more automated computing methods and human-input auxiliary information. Additionally, negative training samples can be collected from the video data based on automated image analyses with respect to the captured video data. The positive training samples and the negative training samples can then be used to train, re-train or update one or more parked vehicle detectors with respect to the parking site(s) for use in managing parking at the parking site(s).