Consider:

100,000,000 cars.

thats 200,000,000 head lights

Say 20 watts each.

Thats 4,000,000,000 watts.

4 GIGA Watts!

Isn't that what the 1955 Dr Brown yelled when he found out how much power his
time machine from the future used?

Anyway that is a considerable number of ever-ready bunnies or somewhat fewer
Nuclear reactors.

And a whole lot of gas for us to buy! Its just not an appropriate solution to
car safety. Better driver training would be cheaper and more effective. Oh, But
then the typical American would have to use their brain when driving. No no no.
Just can't have that.