ISSUE: Whether or not the assailed Letter of Instruction is invalid and violated constitutional guarantees of due process.
FACTS: This is a petition questioning the validity of a Letter of Instruction providing for an early warning device mandatory for motor vehicles. It is assailed in this prohibition proceeding as being violative to the constitutional guarantee of due process in as far as the rules and regulations for its implementation are concerned.
DECISION: No, the LOI is valid.
RATIO DECIDENDI: The assailed Letter of Instruction was a valid exercise of police power and there was no unlawful delegation of legislative power on the part of the respondent. As identified, police power is a state authority to enact legislation that may interfere personal liberty or property in order to promote the general welfare. In this case, the particular exercise of police power was clearly intended to promote public safety. In addition, the UN and the Vienna Convention, both ratified by the Philippine Government recommended the enactment of local legislation for the installation of road safety signs and devices. The Constitution provides that the Philippines adopts the generally accepted principles of international law as part of the law of the land. It is not for this country to repudiate a commitment to which it had pledged its word.