The roads in India are narrow as compared to developed countries. It is advised to hire a private car with a driver or move out in taxi while site-seeing. They are absolutely affordable and very convenient to travel. Cabs are abundant on the roads and there is a widespread network of buses the whole day long. You will find taxi stands located outside all major hotels and malls. During day time you will not find any problem locating a taxi but drivers in India prefer sticking to day schedules so it's difficult to find one after mid-night.
Private cars and taxis are the safest means to travel in India. Although buses are also available from morning 6:00 am to mid-night they are slow as compared to other modes of transport. If you want to explore the real India it is best to hire a private taxi along with a driver. An air conditioned one will make you shell out more but the cost is worth it as the climate in summers is really scorching. Driving yourself may feel better but not in a country like India where most people do not follow traffic rules.
The two-wheelers consider traffic rules with little regard, the car drivers do not mind going from wrong sides on a highway, the motorbikes are very ferry and the trucks are driven at high speeds in narrow roads which is very dangerous. Besides this there are a million wheels on the streets and the roads are highly congested. You may have to wait for long while traveling in traffic jams which are very common.