Park assist works at night. Can you provide more details, such as type os parking attempted (parallel or perpendicular) and whether the boundaries--other cars, buildings, lines--were well defined. Park assist programs will not work in every situation.
Tried lighting conditions of mid-day, full sun, low angle sun, complete darkness. Parallel and Perpendicular. System identified a "spot" less than 10% of the time after passing by it. Tried wide range of distances to cars, gaps between cars, and driving speeds.
Overall impression is the system is not ready for consumer use.