Transcript for New Dangers of Distracted Driving
We are going to turn next tonight here to the new warning about distracted driving. Talking on the phone, even if it's hands free. Can you guess how many seconds it takes for your mind to fully focus back on the road, even after you hang up? Here's ABC's Clayton Sandell. Reporter: Near Chicago, investigators say the driver of this car that ended up crushed under a big rig last night, killing a passenger, may have been texting. Distracted driving is one of the biggest dangers on the road, but a new aaa study says those hands free systems that are supposed to make us safer. Phone, dial Amy smith at work. Okay. Calling Dell reed. Huh? Reporter: Can themselves be highly distracts. Oh, my gosh. I guess that is a stop sign. Oh. Reporter: Aaa tested about a dozen hands free systems. Chevy's rated a mild distraction. Siri on the iPhone rated high. The mazda 6, very high. Chevy and madz dzda did not return our calls today. Most surprising, the study found distractions don't stop when you hang up. Aaa found hands free technologies can keep distracting you, up to half a minute longer. That's enough time to drive three football fields going only 25 miles an hour. Hands free isn't risk free and using your voice to try to interact with the system can lead to levels of disaction that are unsafe. Reporter: Researchers say keep your eyes on the road, and for that 27 seconds, your brain, too. Clayton Sandell, ABC news, Denver. 27 seconds. Thank you, Clayton.
This transcript has been automatically generated and may not be 100% accurate.