When car makers discover a defect that impacts the safety of a vehicle, they are required to notify the National Highway Traffic Safety Administration, as well as vehicle owners, dealers and distributors. What those groups do with that information varies. Accidents continue to cause injuries and deaths even after safety problems are identified and these parties are informed.
Part of the problem is that the motivation to have the repairs done is different depending on the person in charge of the vehicle. Rental car agencies may be reluctant to take a group of cars out of their fleet even though the cost of repairs is paid by the auto maker. Not all car owners are in a position to have repairs done when they receive a recall notice in the mail. Finally, despite the effort that goes into publicizing a recall, there are many cases where a vehicle owner is not aware that a car is in need of important repairs.