Part of the problem is that we are a nation of varying regulations regarding handsfree use, making it harder for a tech company to go to market with a single solution that will A.) answer a need that maps tightly to what the local laws ban and B.) interest consumers that are mostly at war with themselves in terms of wanting to use mobile services in the car while also knowing that causes distraction.
I don't know if the case was resolved, but Apple was being sued in a class action for failing to prevent in-car phone use, something the suit alleges handset makers can easily do:
https://www.cnet.com/news/apple-blamed-for-accident-sued-by-injured-driver/
It seems a simple thing to use some combination of GPS speed estimation and Bluetooth connection state to reasonably determine if a phone is in a car and then block much or all of its functionality. But, as some posters here have already noted, discriminating a passenger's phone from a driver's is tricky. And, in the case of a teen driver, you don't have a willing participant in the scheme.
Further progress may come from proposed federal regulations regarding brought-in electronics in the car:
https://www.nhtsa.gov/staticfiles/rulemaking/pdf/Distraction_Phase_2_FR_Notice_11-21-16_final.pdf
In a nutshell, the feds want the auto and mobile industries to work together to make their products recognize each other in a robust way, determine if the mobile device is being used by a vehicle operator and then either block functions or make them extremely digestible via the vehicle's own interface, which is assumed to be safer than juggling a phone.
"Lock outs (would) include:
• Displaying video not related to driving;
• Displaying certain graphical or photographic images;
• Displaying automatically scrolling text;
• Manual text entry for the purpose of text-based messaging, other communication, or
internet browsing; and
• Displaying text for reading from books, periodical publications, web page content,
social media content, text-based advertising and marketing, or text-based messages."
I don't know where Keith T.'s granddaughter resides, but here in CA the rules are already much tougher than what the feds are only considering. Since January. CA has had an almost complete handsfree regulation, allowing only a single swipe or tap to activate voice mode. It is a primary offense unless, interestingly, you are a minor in which case it becomes a secondary offense you cannot be stopped for on its own
http://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH§ionNum=23124