Power distribution system architectures are described that can safely and effectively support the power needs of automotive original equipment manufacturer (OEM) systems and state-of-the-art autonomous systems and devices. In some implementations, a power distribution system may include: vehicle power sources that produce an output voltage to operate one or more devices in the vehicle, and power bridge devices that electrically couple a vehicle power source to the multiple banks of battery bridge devices and to power distribution units (PDUs). Various electrical loads in the vehicle can be electrically coupled to the battery bridge devices and to the PDUs.