Is this typical of many border collies?

When we take our pup (four months old) out for walks, at first he seemed scared of cars. Now, however, he crouches low on the ground waiting for them to go past and tries to pounce on them like sheepdogs often do when herding. Obviously he is on a lead near roads, but I was just wondering if this is a natural herding instinct that many border collies have?