From your first link: "Getting a driver's license after turning 16 years old has become a lengthier process in recent years, as regulators instituted more safety hurdles. That has also led to a sharp decline in teenagers who are driving."
That said, this is going sideways because I didn't make a complete and clear post originally. Never mind.
http://time.com/money/4185441/millennials-drivers-licenses-g...
http://www.npr.org/2016/02/11/466178523/like-millennials-mor...
https://www.washingtonpost.com/news/wonk/wp/2014/10/14/the-m...
http://www.csmonitor.com/USA/USA-Update/2016/0120/Why-are-Mi...