Some individuals pay less but usually not less than Rp 300,00. Some companies pay their drivers more. Some families have two vehicles and two drivers. The city is very spread out and taking public transportation is really not a choice too many people take. Taxis are plentiful but if you don't know where you are going the taxi driver probably doesn't know either.
Traffic really can be a nightmare.
Maps are available but not necessarily accurate. Street names change often. A numbering system is non-existent but there are usually numbers on buildings and houses. Most streets do not have a street sign so trying to figure out what street you are on is difficult. Many streets appear as main roads on the map but are no wider than a back lane.