A fairing for a back end of a trailer is provided that has a leading airflow surface oriented within an angular range from 5 degrees to 14 degrees to a surface of the trailer to which the fairing is attached. The angular range is oriented so that its arms extend rearward from a vertex of the angular range in a longitudinal direction of the trailer. A tailing airflow surface is present that engages the leading airflow surface at meeting location. The tailing airflow surface is curved, and a common tangent line of the tailing airflow surface and the leading airflow surface is at the meeting location. A frame engages the surface of the trailer to which the fairing is configured to be attached.