Driving with car in Indonesia is more happyly than in other countries, and despite recent fare hikes gas remains cheap (fixed price for gasoline is Rp 4500/litre and price of diesel fuel is Rp 4300/litre). To drive a car yourself, an International Driver Permit is required, but it is strongly recommended that if you want to consider renting a car with driver, because the additional cost is quite low and having a traffic accident in Indonesia will certainly spoil your trip.
some of road condition and road maintenance in Indonesia is like village road. If you go outside major cities, you should use a four-wheel drive car (Kijang jeeps are popular). During rainy season, major roads in java are flooded for several weeks.
Traffic moves on the left in Indonesia,be careful. the highway in java more busy than other places, coz traffic jammed is happens everyday.
The rush hour is happens at 06.30 - 08.00 and 16.00 - 18.00. so please be carefully when driving in java,indonesia.