Question & AnswerQ&A (LTO MEMORANDUM CIRCULAR NO. 94-192)
The main purpose is to abate excessive smoke emission from diesel-powered motor vehicles to promote public health and environmental safety.
It applies to all diesel-powered motor vehicles prior to registration in Metro Manila and those already registered found to emit excessive smoke while operating on public highways.
Section 34(1) of Republic Act No. 4136 and Presidential Decree No. 1181 authorize the implementation of the smoke emission tests.
The black soot content must not exceed 2.5 m-1 light absorption coefficient or 48% on the Iyasaka Bosch or opacity-type meter, or 66% on the Hartridge smoke emission unit (HSU) or equivalent testers.
The test is done on a stationary vehicle at normal engine operating temperature without fumes escaping or dilution. The free acceleration feet procedure is observed, involving engine acceleration and measurement of smoke opacity using calibrated equipment, repeated until readings stabilize.
The test result is the arithmetic mean of three stabilized consecutive free acceleration tests and is recorded automatically by the computer system, printed, and attached to the Motor Vehicle Inspection Report (MVIR) and given to the vehicle owner.
The test is valid for 30 days from the date conducted and may be taken within one month prior to registration.
Fees collected are: Fifty pesos (₱50) for vehicles under L, M, H, UV, and TX categories; Seventy-five pesos (₱75) for vehicles under T or TB categories; and an additional ₱50 for tests conducted at the owner's garage.
The smoke opacity of all exhaust pipes is measured, and the highest reading is used to determine compliance with emission standards.
Yes, after the test, the full-load screw of the injection pump or delivery system must be sealed to prevent tampering.