Hi Gaurav,
Your idea sounds very good and practical. I suggest you to use image processing other than poor IR sensing. You have to use DSP’s if you are implementing the image processing. For all others I think any common microcontroller would do.
Now my question is that, we all have been hearing about this kind of vehicle and projects since a very long time. But they still remain as prototypes only. So how do you plan to make your project stand out of the others and become a practical one for real vehicles and real roadways.