And we begin with the growing concern this evening over those air bags in millions of cars on American highways right now. Are your air bags at risk of exploding? Tonight, the 911 call you're about to... See More
And we begin with the growing concern this evening over those air bags in millions of cars on American highways right now. Are your air bags at risk of exploding? Tonight, the 911 call you're about to hear. And we all know how they're supposed to work. The air bag deploys, you can see the test dummy protected in this video right here. We first reported last night here about the pieces of metal that can be sent flying. One safety expert telling us it's like an ied going off in your front seat. Tonight here, the police who answered the call after a car accident. They thought the driver had been attacked. Tonight, they believe it was the work of her air bag. ABC's Brian Ross again this evening. We got a lady who just got killed in a car wreck. Reporter: The recall follows a bizarre traffic accident last month in Orlando, Florida with a dramatic dual 911. He just pulled her out of the car. He says her neck is severed. Reporter: Sheriff's deputies first thought hind Tran had been murdered, given the injuries to her neck. They even released a photo of a possible person of interest who they have now cleared after learning the air bag in her Honda was one of those like this one under recall because of the possibility it could explode and send dangerous metal sharld shards flying through the car. Based on the evidence, they're leaning towards that decision, too. Reporter: If confirmed, safety advocates say it would be the fourth death connected to air bags that did not perform as they are supposed to. And now, more than 4 million motorists are being warned to immediately replace the air bags in their vehicles. This is like having an ied in your car. When it explodes, it sends shrapnel into the vehicle and peppers the occupants, causing lacerations and death. Reporter: The defective air bags are just the latest example of what safety advocates say has been the repeopled failure of federal officials to protect the public from highway hazards. Includi including, as ABC news has reported, highway guardrails which are supposed to be able to absorb a head-on impact as seen in this crash test video. But today, there were demands from congress for action in the wake of a growing number of gruesome injuries and deaths in guardrail accidents. And, a court finding Monday that the manufacturer essentially lied to the government about the guardrails. They ought to take action to protect motorists, whether it's a recall or some kind of repair to the internals that apparently can operate like a harpoon or a sword when these guardrails are supposed to be absorbing the impact. Reporter: And late today, the federal highway administration ordered the guardrail company, Trinity strips of Texas, to perform nor crash tests on their product or threaten they would be suspended or revoked for use around the country. Brian Ross leading us off tonight. Thank you.
This transcript has been automatically generated and may not be 100% accurate.