Drivers are slow to adopt blocker apps that limit the functionality of a cellphone when a vehicle is moving but open to being encouraged to do so, reveals a new survey from the Insurance Institute for Highway Safety (IIHS).

In fact, just 20% of owners of iPhone 6 and newer models have Apple's Do Not Disturb While Driving feature set to automatically turn on when driving or connected to a car's Bluetooth.

Users of Apple's app can opt in to automatically direct calls to voicemail and send a preprogrammed message to texts while driving, or turn the feature on and off manually each time they get behind the wheel. Either way, the app is intended to help curb distracted driving.  

While adoption is slow, 75% of survey respondents who had used the blocker feature in the past month agreed that it isn't annoying and should be an automatic feature for all cellphones.

In addition, most drivers who had used it recently said they were aware they could override it, but seldom choose to do so.

Of those who chose to manually set the feature versus use the app automatically almost 40% said they would be open to receiving a reminder prompt from Apple motivating them to try the app again.

Finally, 19% of drivers with Androids or older iPhones said they have a cellphone blocker, yet only 50% of this group said they use it all or almost all of the time. The majority of this group somewhat or strongly agreed that cellphone providers should put blockers on phones that work like Apple's app.