This RNZ story about police cracking down on drivers' use of mobile phones concludes with this paragraph:
"And cellphone companies themselves are coming up with solutions, with some phones automatically shutting down once a vehicle is travelling at a certain speed."
Most people are addicted to the pings coming from their phone and have an irresistible urge to check - even while driving.
Looking at the hierarchy of controls, and starting at the bottom, PPE doesn't really apply, and no amount of training (or fear of getting a ticket) will overcome addiction and our urge to check.
If all phone companies agreed to render their phones inoperable when they detect travel at a certain speed, that would be a form of engineering control which would eliminate the risk.
I take the point about GPS, but texting and talking on the phone (yes, even hands-free) is a known fatal risk which has already caused dozens of deaths in NZ and will inevitably cause hundreds more.
Such risks cannot be minimised by trying to develop better habits. That's like asking a machinery operator to not put his hand in the machine to clear a jam. You can train, train, train on this but human nature always takes over. Elimination of the risk by introducing an engineering control is the way to go for machinery - it takes the human element out of it (if done properly).