States with some type of texting while driving ban experienced a 4% reduction in emergency department visits after crashes, according to a new study reported by CNN.

Moreover, states that implemented primary bans on all drivers saw an 8% reduction in crash-related injuries.

The data suggests that primary ban laws — where drivers can be pulled over for texting regardless of another traffic violation — offer an even greater safety benefit than secondary ban laws. In addition, the study findings suggest ban laws appear to work best when applied to all motorists versus just new drivers.

To conduct the study, researchers examined emergency department data spanning 16 states between 2007 and 2014, reports CNN. Of the 16 states, all but one (Arizona) had some type of texting while driving ban on the books.

Presently, 47 out of 50 states have laws that prohibit texting behind the wheel. Arizona, Montana, and Missouri remain the exceptions.

The lead author of the research points to two limitations of the study, notes CNN. It did not measure how well laws are implemented in different states and it did not include all 50 states.