I have no idea whether this kind of transportation is exist or otherwise outside Jakarta - Bekasi
Omprengan is illegal public transportation originally from private cars being multi functioned by the owner to bring other people who has the same destination.
So, if the owner domiciled in Bekasi but has to work in Jakarta. Rather than he deal with gasoline and highway fare alone, it would be better if he share with other people who are about to go to the same destination. Passengers prefer omprengan because even though is more expensive but at least they could avoid the tiredness for standing along the way inside the bus. Or the fare could be cheaper if the passengers need to take public transportations more than one before reaching the destination. This is only in smaller scale where the owner operated his vehicle to shares fare and in limited capacity also still prefer the comfortableness.
There are other omprengan operated almost like public transportation. They have their own base camp and not going to move before they have full passengers inside the car. Comfortableness be gone... But still people prefer to use omprengan as public transportation has becoming more disaster.
Although I worked inside the city, once for a few years I enjoyed using omprengan. Well, it was not really that comfort as the vehicle was an old minibus. But it has huge space so within force there could be 15 people inside.
The happy side? Obviously because the fare is cheaper compare to the bus. And I could sit and sleep all the way. My goodness, I really don't want to miss a chance to fall asleep...
The not so happy side because the driver always waiting for his loyal customers for a long time. Most of his customers start working at 08.30 AM so they were not in a hurry.
The funny or tragic story was the moment that I saw how people who were having too much comfort could ask for more. At that time, the gasoline price was increasing. So, the driver ask for our understanding that he would increase the fare as well. A lady asked me in vain,"Oh why he has to increase the fare?" So, she really not willing to pay more. I looked at her while thinking if she use the bus then she has to pay more than she paid right now. And there would be no chance to have a bit of comfort.
The danger of using unknown omprengan is the owner could be a robber along with the fake passengers. Which is why don't take chances when we are about to use omprengan for the first time. It would be best if we have someone who familiar with it.
Sure we need cheap fare but we always need to be alert.