Urban public transport has potential roles in integrating approaches, from technology advancement to behavior shift, to decouple CO2 emission from mobility. Cities in the developed world have adopted various policy instruments to develop public transport niches, but knowledge is still limited to explain how fast-growing cities in developing countries take a similar step. We aim to analyze the ways a mix of policy instruments in Indonesia are designed to facilitate urban public transport niche development for the transitions. We combine the framework of shielding, nurturing, and empowerment (S/N/E) for niche development with the policy mix concept to examine 62 regulations from the national to the city level in which Jakarta is selected as a case study. We discover that existing regulations are not deliberately set up as an integrated package to help the niche development amidst ample enabling instruments for the transitions. The promotion of the Electric Vehicle Program (EVP) is not yet fully aligned with other public transport measures in Jakarta to target emission reduction or energy conservation. Our results reflect a need to make the transitions relevant for policymakers at the sub-national level that can be done through sustained collective policy learning during the niche development.