Welcome to ETO, Gerardog2000!
You asked...
.
I'm old school. I'm convinced that the more cars are made "smarter", the dumber the drivers become.
And don't get me started on the complexity of the engine and safety features (most ECU controlled) of cars utterly aggravating (read raising) costs of "repairs" disguised as simple ECU upgrades. I mean, $75-150USD
just to hook up to the OBDII and enable/disable something? Please...
Anyway, as for your idea.
You might investigate your concept as it would apply specifically to hybrids (since full electric cars, as the norm, are coming). A brake locking scheme might be rather easily implemented though software (code) that would
electrically lock the brakes through the electric motor component of the drive train (it's already involved on the braking process). Seems that all the pertinent data (speed, brakes application, wheel rotation, TPS data, etc.) would be at hand and a small
locking current to the motor might be sufficient to keep the vehicle in place until the throttle is re-engaged.