How many people can ride a motorcycle? In some parts of the Philippines, this two-wheeled vehicle can carry 10 passengers with their baggage. This unique mode of transportation is called Habal-Habal or Skylab.
Habal-Habal is a popular way of travelling in many areas of Mindanao, located in southern Philippines. It is used especially in remote villages with rough and narrow roads. Farmers also need the Habal-Habal to transport their goods to the market.
Skyscanner cites the value  of the Habal-Habal:
In Metro Manila, it is an everyday picture that you see 1 to 2 persons riding on a motorcycle. However, it is not the case when it comes to the streets of Mindanao and some parts of Visayas.
Habal-habal is a highly improvised two-wheeled single motorcycle usually ridden beyond its passenger capacity. Since it is used as public transportation especially in areas with narrow roads, and steeper, rougher terrain, it could possibly carry up to 6 passengers, at the least. Yes, some people might have said that a habal-habal could accommodate more than 10 persons, with baggages ranging from vegetables and groceries to livestock like chicken yet to be included.
TravelingMorion is amazed at the driving and balancing skill  of the Habal-Habal driver:
A big help to locals usually living in mountainous areas wherein roads are mostly not accessible by 4 wheel vehicles. Interesting about this mode of transportation is that the ability/skill of the driver to balance considering the weight of the passengers from side to side, front, plus another 3 to 4 persons at his back.
In order to carry many passengers, the motorcycle is fitted with wooden planks. It’s one reason why many people called it Skylab :
Habal-Habal is now used interchangeably with the word “Iskaylab,” believed to be taken from the damaged U.S. space satellite named “Skylab” that plunged to Earth from space in 1979. Other conflicting account suggests a contraction of the phrase “sakay na, lab!” which literally means “get on, love!” Personally, it is my opinion that the term was most likely adopted from the former than the latter because of the wooden plank extension placed at the back seat across the motorcycle's main body which serves as additional seat to hold more passengers and, therefore, closely resembling the Skylab and its protruding satellite wings.
Doctrine once saw a Habal-Habal ambulance  and got disappointed with the government:
It makes me angry to see many such ambulances in Metro Manila being used for personal travel while communities in dire need of emergency vehicles can only improvise with the habal-habal to get people to hospitals.
It’s a shame that our government can spend a lot or engage the private sector in major projects while hundreds or even thousands of communities remain under-served for basic needs including access to schools, hospitals and workplaces.
slow down…skylab. pic.twitter.com/liSapEbDo6 
— Chris Dalisay Jr. (@chrisdalisaymd) March 30, 2014 
one of the transportation in the visayan region…HABAL-HABAL… pic.twitter.com/e7dpHq9SDP 
— allan (@allanbergonia) November 21, 2013 
Some Habal-Habal has tarpaulin roofs:
— Bogart the Explorer (@BogartDexplorer) October 8, 2013 
— PɹoLıɟǝ Apʌoɔɐʇǝ (@1nGG0t) March 17, 2014 
Despite its popularity, the Habal-Habal is actually an illegal mode of public transportation. Although a Mindanao legislator recently proposed  to legalize the operation of the Habal-Habal.
— Noel Casubha (@noelcasubha) March 6, 2014