One problem related to back up alarm has been reported for the 2007 Toyota Prius. The most recently reported issues are listed below.
All late model Toyota gas electric autos. I find them very dangerous in parking lots, as they can and do backup with no noise. I was almost run over by one on a foggy day last week. The driver never turned on light and didn't see me when backing out of parking spot. I was able to get out of the way that time. Suppose I had been blind? not a sound to let me know the car was there. I really think the car company should install a backup alarm of some sort on all these autos.