Air Tabs

dos those make cars go faster?

…they distrupt the laminar flow of air (similar details are molded in to f1 helmets to keep 150mph air from sucking the drivers head up from behind the windscreen)…obviously also very useful on trips to the grocery store in the familly suv or when high speed towing a loaded cargo trailer.

Sure, they have an effect. Mostly on large long-haul trucks, and even then only at high speeds.

The aerodynamics of a modern car only really start to come into effect at about 40mph and greater. Below that speed the force is pretty negligible. I don’t debate that they do work, but I’d rather drive a smaller car in a high gear than pay extra for those things and make my car look dorky. 7 to 10 percent greater fuel efficiency is easy to attain by driving 10 mph slower or shifting sooner.