A cargo transport heating system for a tractor-trailer system comprising a tractor having a combustion engine, and a trailer having a cargo containment, the combustion engine having a first coolant inlet and a coolant outlet; a heat exchanger disposed in the cargo containment, and in fluid communication with the first coolant inlet; an engine supply conduit extending between, and in fluid communication with, an outlet of the heat exchanger and the first coolant inlet; a coolant pump in fluid communication with the coolant outlet and in fluid communication with the heat exchanger; a supply conduit extending between, and in fluid communication with, the pump and the coolant outlet; a non-toxic combustion engine coolant, wherein the coolant pump pumps the non-toxic combustion engine coolant through the first coolant inlet, the coolant outlet, and the heat exchanger; and a controller; characterized in that the system comprises: a cargo temperature sensor disposed in the cargo containment for measuring cargo air temperature, wherein the cargo temperature sensor is configured to output a cargo temperature signal to the controller; and an engine temperature sensor configured to measure engine temperature and output an engine temperature signal to the controller, wherein the controller is configured to receive the air and engine temperature signals and based, at least in-part, on the air and engine temperature signals, output at least one command signal to at least one of a flow control valve, the coolant pump, and an engine coolant heater. a tractor having a combustion engine, and a trailer having a cargo containment, the combustion engine having a first coolant inlet and a coolant outlet; a heat exchanger disposed in the cargo containment, and in fluid communication with the first coolant inlet; an engine supply conduit extending between, and in fluid communication with, an outlet of the heat exchanger and the first coolant inlet; a coolant pump in fluid communication with the coolant outlet and in fluid communication with the heat exchanger; a supply conduit extending between, and in fluid communication with, the pump and the coolant outlet; a non-toxic combustion engine coolant, wherein the coolant pump pumps the non-toxic combustion engine coolant through the first coolant inlet, the coolant outlet, and the heat exchanger; and a controller; characterized in that the system comprises: a cargo temperature sensor disposed in the cargo containment for measuring cargo air temperature, wherein the cargo temperature sensor is configured to output a cargo temperature signal to the controller; and an engine temperature sensor configured to measure engine temperature and output an engine temperature signal to the controller, wherein the controller is configured to receive the air and engine temperature signals and based, at least in-part, on the air and engine temperature signals, output at least one command signal to at least one of a flow control valve, the coolant pump, and an engine coolant heater. a cargo temperature sensor disposed in the cargo containment for measuring cargo air temperature, wherein the cargo temperature sensor is configured to output a cargo temperature signal to the controller; and an engine temperature sensor configured to measure engine temperature and output an engine temperature signal to the controller, wherein the controller is configured to receive the air and engine temperature signals and based, at least in-part, on the air and engine temperature signals, output at least one command signal to at least one of a flow control valve, the coolant pump, and an engine coolant heater.