The attributes of the different lights I used are shown in Fig.10.
Rendering and Render Layers
For more control and to improve my skill set, I wanted to create a handsome amount of layers so that I could handle the compositing freely. You can see the render layers window in Fig.11.
My render included the main passes, like beauty for the car and environment, occlusion, reflections of the lights on the car, Z Depth for the blur purpose etc (Fig.12).
The initial comp can be seen in Fig.13 (e.g., the environment beauty, the car beauty and the occlusion pass).
The shadow of all the lights were very soft because I wanted to get the shadow information from the occlusion pass and hence minimize the render time used in calculating the shadows.
One more thing to mention is that I used Final Gather for the bounce effect of the lights, for which the interpolation value was different for the car and the environment. Interpolation is used to minimize the blotchy effect of Final Gather points. I kept the values of the accuracy and point density the same, in the Final Gather options. You can find the settings in Fig.14.