The limits in this SAE Standard are designed to provide protection for receivers of all types of radio transmissions when used in buildings. As a result, receivers of radio transmissions used out-of-doors may not be protected by the limits specified. This publication applies to the emission of electromagnetic energy which may cause interference to radio reception and which is emitted from: a. vehicles propelled by an internal combustion engine, electrical means or both (see SAE J551/1 for definition); b. motorboats propelled by an internal combustion engine, electrical means or both; and c. devices equipped with spark-ignited internal combustion engines (see SAE J551/1 for definition). This publication does not apply to aircraft, traction systems (railway, tramway, and trolley bus), or incomplete vehicles.