The percentage of distracted drivers operating their vehicles on roadways at any given time may be as high as

The percentage of distracted drivers operating their vehicles on roadways at any given time may be as high as 49% (according to survey´s AAA Traffic Safety Foundation)

Explanation:

The AAA Traffic Safety Foundation conducted a survey that determined that 49 percent of respondents admitted using a phone while driving, the AAA survey determined this of 2613 licensed drivers throughout the United States who were 16 years old or more between October 14 and November 17, 2017.

Drivers are distracted by navigation systems, eat, make up etc.

it is the most commonly accepted one