The great number of trailers on the highways has resulted in expanded regulations covering lights and reflectors, and car power circuitry now needs to be made compatible with increased lighting requirements. Standardization is needed with respect to the connection of trailer lights and the grounding of trailer frame to car frame, as well. A standardized car-trailer connector suitable for use in more than one combination of trailer plug with a single-receptacle car connector is another necessity.
These requirements suggest the advisisability of developing recommended practices for the above situations. An SAE standard should also be prepared to include portions of current SAE electrical standards now applicable to car-trailer lighting and featuring an expansion into new problem areas in this field.