I kind of liked the idea of a "smart steering wheel"
If for any reason, the driver takes either of their hands off the wheel, then their paired phone will automatically lock, and they can't place or answer calls when moving,
except by using voice commands and a hands-free device.
What good would this be, why not just use the existing method of locking the phone while it's in motion? Or, do you mean to have a way for all other phones in the vehicle to somehow also pair and abide by the steering wheel hand sensor, thereby allowing passengers to text only when the driver is being "safe"? Why not just have a working phone act as a key to the car, which then becomes locked (presumably its the driver's phone) and therefore who ever isnt the driver has a working phone still? Better yet, have electronic "driving gloves" in the car that are required to have hands firmly in them in order for the engine to run, which will naturally stop the user from being able to operate a touchscreen while driving (unless they have a blackberry or happen to be Bennett Hasselton, two punishments worth more than the crime of texting while driving anyway.)
The unfortunate thing is that drivers have a really endless list of dangerous shit they can do behind the wheel (ghost riding the whip, anyone?) and passengers do, too (watch any given episode of tosh.0 for hints) so bending over backwards to stop serial texters is probably not worth the trouble. Give cops good ways to spot and cite it, let the offenders get penalized, and if they dont stop then take their license away. Pretty simple, really. Alcohol, at least, has a chemically addictive component that isn't easily forsaken which calls for more specific punishment to encourage rehabilitation. Texting and driving is perhaps only rehabilitated if you take away the offender's friends.