Umm, so as far as I understand velocity is speed in a direction. So if I'm going North at X Km/h and another guy goes south, he'll go at -X Km/h. So anyways, the formula for relative velocity, for example V(AB) is V(A)-V(B). So let's say two trucks are going at 70 m/s towards each other (they're gonna gonna crash :P). So the velocity of Truck A relative to Truck B will be 70 m/s - (-70 m/s) = 140 M/S. Now since this is velocity, doesn't this imply that Truck A is going parallel alongside Truck B instead of going the opposite direction. I'm really sorry if this is a stupid question, this is just a new concept and I don't fully understand it.