The letter said that manufacturers rarely have an accurate count of the particular vehicles in a rental car fleet because they are often sold quickly and the new ownership is sometimes not registered until months later. Therefore, the letter says, the total numbers of vehicles reportedly owned by the companies while under recall will always be higher -- at times significantly -- than the actual number.
The letter also noted that sometimes an inspection or repair of a vehicle under recall goes inadvertently unreported, lowering the number of fixed cars.
But to Clarence Ditlow, executive director for the Center for Auto Safety, any percentage of fixed cars rented out under 100 percent is unacceptable.
"They cannot pick and choose," Ditlow said. "They're gambling with your life."