SEMA’s (Special Equipment Market Association) Market Research Department conducted a study to test the affect tonneau covers have on the coefficient of drag for pickups.

Four trucks were tested: a 2006 Ford F-150 with a 5' 5" bed; a 2005 Ford F-150 with a 6' 5" bed; a 2006 Dodge Ram 1500 with a 6' 5" bed; and a 2007 GMC Sierra with a 6' 5" bed. These trucks were tested at the A2 Wind Tunnel in Mooresville, North Carolina, with 13 different tonneaus from nine different manufacturers.

The wind tunnel test produced great results. All 13 products tested improved the coefficient of drag, Cd, by at least 4.2%. The improvements ranged anywhere from 4.2%–7.8%. Other tests would need to be conducted in order for fuel economy to be calculated, but it is safe to say that a reduction in drag would improve fuel efficiency for these pickups.