Air Deflector Van + Cargo Trailer Fuel Improvement

If you google this subject you will find lots of equally unscientific studies. The mpg improvements with an air deflector are likely to be very small and only present at high speed driving. The extra weight is likely to yield negative results at lower speeds.

Anyone interested can google testing by the YouTuber, Marion Blair. He found no benefit to offset the cost of installing a deflector. His studies seem to be a bit more scientific than most.