Make sure your vehicle has a seat belt!
Indian drivers are insane.
You will encounter similar drivers in a belt stretching from Turkey all the way to India.
The drivers in India will take enormous risks.
I recall a bus driver playing chicken with a lorrie (transport truck).
At the last minute this guy manages to get back into our lane with the bus unscathed.
In a bus that is overcrowded a seatbelt is the least of your worries-try getting a seat!
My advice though is DO NOT drive on your own-instead hire a driver. Chances of getting hurt while driving are high, since one may not know the road 'etiquette'.
A good way to travel is the Indian Rail System, eventhough it is archaic and once again overcrowded at least you eliminate the road hazard.
If I remember correctly you have to really book in advance to get an A/C car on the train otherwise you will be cooking and sweating like a porker.
One more thing, most of the 'toilets' on the train are 'latrines' i.e., you squat to do your thing and you should carry TP as there may be none available.
Happy travelling