AI in a Driving Simulation

I am doing research on the driving simulation area. I would like to build a city enviornment with Unity3D.

In terms of the autonomous cars in the enviornment, is it a good solution using waypoints to control their paths? The problem is do i need to have a group of waypoints for each car?

Would anyone help me with the solution in terms of interaction with and controlling autonomous vehicles in a driving envirnment.

I would do a search on ai, pathfinding, a*, UnitySteer is an interesting package you might want to check out Sarge also it has a lot of stuff to pique your curiosity even more. The web is full of resources. I have been looking into the the same material and, the question is how would you like the individual CARS behavIORto be.