The "wolverine" tire stud idea isn't so implausible as you think. Combined with "airless" tires, having retractable studs would be a rather simple mechanism.
What follows next is a Federal mandate that all cars made after such-and-such date will have these retract-a-stud tires on them, raising the average price of a new car by thousands, on top of all the other Federally mandated "safety" equipment that started out as optional luxury upsell items (i.e. seatbelts, airbags, ABS, TPMS, rear cameras, and eventually "collision avoidance" systems). Sure they're nice to have but they put the price of a new vehicle out of the reach of the common man.
Where did the days when a man was free to maim or kill himself and others through his own stupidity go?
