Hands-free tech in cars and smartphones are meant to make driving safer, but a new study finds that they’re just as bad a distraction as any. In research for the AAA foundation for Traffic Safety, scientists from the University of Utah found that it takes a full 27 seconds to regain attention after issuing voice commands.

According to the U.S. Department of Transportation, over 3,000 people died in accidents involving distracted drivers in 2013, and an additional 424,000 were injured.

The researchers came to their conclusions after collecting data from two studies. One asked participants to rate the distraction level of smartphone “personal assistants,” looking at Microsoft’s Cortana, Apple’s Siri, and Google Now. The other focused on distractions caused by hands-free functions built into cars, like the Chevy Malibu’s MyLink program and the Ford Taurus’ “MyFord Touch.” In both, the participants — none of whom had caused any traffic accidents in the past five years — drove around a 2.7-mile Salt Lake City loop at 25 mph while using the devices.

Whether they were helping make voice calls, change music, or send texts, all of the smartphone PAs were considered “highly distracting” by the 65 participants involved. Ditto the in-car functions, which 257 participants considered moderately to highly distracting.

Despite its good intentions, voice command simply isn’t that reliable, and so it’s more of a hazard than a protective measure.

And, as the authors point out, voice command is now being used to entertain drivers rather than aid them, so even if the system keeps hands focused on driving, it doesn’t mean eyes and minds will be. The 27 seconds it takes to regain attention after disconnecting from a highly distracting system is enough for a car traveling 25 mph to travel the length of nearly three football fields, the authors report. A lot can go wrong in a stretch of time and space that long, especially if your mind is still busy cursing out Siri.

“Most people think, ‘I hang up and I’m good to go,’” said senior author David Strayer, in a press release. “But that’s just not the case. We see it takes a surprisingly long time to come back to full attention. Even sending a short text message can cause almost another 30 seconds of impaired attention.”

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