Is flying the published ODP for the runway used for takeoff mandatory?

Flying the published Standard Instrument Departure (SID) or Obstacle Departure Procedure (ODP) is generally optional unless specifically stated otherwise in the relevant procedures or air traffic control instructions. ODPs are designed to ensure a safe departure while avoiding obstacles and providing a structured route out of an airport, but pilots are not required by regulations to fly them unless a specific clearance or requirement necessitates adherence to the published procedure.

It's important to recognize that pilots have the discretion to determine the best route for departure based on their scenario, other traffic, or aircraft capability. This flexibility allows for the safe management of departures especially when conditions change or when flying in less than ideal scenarios. Thus, adhering to the ODP is not mandatory unless explicitly indicated by air traffic control or procedures in a given situation.