There are two important international conventions or agreements that the Philippines is a signatory to. These are the
Vienna Convention on Road Traffic (November 8, 1968):
and the Vienna Convention on Road Signs and Signals (November 8, 1968):
These are important as signatories are bound but the agreements on road traffic rules and regulations and standard signs and signal. I included the links to each agreement as they also include the exceptions taken by different countries such as Thailand and Vietnam declaring they will not be bound by Article 44, choosing to classify mopeds as motorcycles. Apparently, the Philippines did not declare exceptions or objections to any of the articles.