Two new studies have found that voice activated smartphones and dashboard infotainment systems may be making the distracted driving problem worse instead of better.

The systems let drivers do things like tune the radio, send a text message or make a phone call while keeping their eyes on the road and their hands on the wheel, but many of these systems are so error-prone or complex that they require more concentration from drivers rather than less.

One study examined infotainment systems in some of the most common auto brands on the road: Chevrolet, Chrysler, Ford, Hyundai and Mercedes.

The second study tested the Apple iPhone's Siri voice system to navigate, send texts, make Facebook and Twitter posts and use the calendar without handling or looking at the phone.

Apple and Google are working with automakers to mesh smartphones with infotainment systems so drivers can bring their apps, navigation and music files into their cars.