The accords make financial sense for the settling parties, but Takata and other defendants, including Honda Motor Co., General Motors Co. and Fiat Chrysler Automobiles NV, get an extra advantage in keeping damaging information out the hands of outsiders interested in suing them. The quick, secret deals -- a cornerstone of product liability litigation across industries -- help explain why years after the first recalls so much remains unknown about defects linked to four U.S. deaths. The few cases filed have generally been resolved before victims’ lawyers acquired evidence.

Five of a dozen lawsuits reviewed by Bloomberg News were settled before information could be revealed in courts. One of the cases is being reviewed for a possible settlement, while one is in mediation and another was dropped. None has gone to trial.

The lack of information deepens the confusion surrounding an escalating crisis. Recalls of more than 7 million vehicles by at least 10 carmakers have left drivers unsure about whether they’re at risk. Safety advocates blame the National Highway Traffic Safety Administration for not doing enough in its probe of Takata while a federal grand jury has sent the company a subpoena to turn over documents and explain the defects with its safety devices.