animate models in Unity

I have a scene prepared with car models included, just looking for someone to write the C# script that will animate the cars along the road to simulate simple traffic flow. Animation should start automatically, no buttons required. Script should randomly choose a car models and speed(reasonable range) on each lane and launch to create simple traffic flow effect. I've included the video which exactly describes my requirement. (I've provided same scene and models from the video) Project files will be uploaded after the winning bid.