This is not a Tagalog word.
It’s an English acronym for “Anti-Smoke Belching Unit” whose team members you can see stopping vehicles in the Philippines to check if the vehicle emissions are acceptable.
ASBUs are run by local government units (LGUs), who are permitted by the 1999 Clean Air Act (RA 8749) to set up roadside inspections systems for motor vehicles suspected of being smoke belchers.
RA = Republic Act
The Philippines is constitutionally known as the Republic of the Philippines.
Many Filipinos question the legality or at least inconvenience caused by ASBUs who seem to randomly stop cars in the middle of the roadways, causing traffic backups. Cars are supposed to be inspected annually for emissions under the Land Transportation Office (LTO), yet despite having papers proving they’ve undergone the annual inspection, many cars are still put through on-the-spot emissions tests. ASBU members have been known to accuse the LTO of corruption.