According to at least one aspect, embodiments herein provide a traffic light power management system comprising a power source, a first output, a service bypass unit and a power management unit. The service bypass unit is configured to receive AC power from the power source, convert the AC power to a first DC power in a first mode of operation, provide the first DC power to the first output in the first mode of operation, and provide the AC power to a power management unit in a second mode of operation. The power management unit is coupled to the service bypass unit, and is configured to receive the AC power from the service bypass unit in the second mode of operation, convert the AC power to a second DC power in the second mode of operation, and provide the DC power to the first output in the second mode of operation.