We don't want to turn cars into horses. Have you ridden horses? They sometimes do stupid, dangerous things with no notice and it takes an experienced, attentive rider to stay in control. Like I saw a horse panic and almost buck her rider off when she was startled by a snake. Another horse seriously injured a friend of mine when it freaked out in a horse trailer and started kicking.

Don't get me wrong, I love horses. But they're living creatures with minds of their own and you have to always treat them with a certain wariness.