Nope, no engineering degree. I didn't even stay at a Holiday Inn Express last night. But I can show you papers written by engineers and experts in the textile industry confirming that information. Google is your friend. Harness manufactures and SFI have to rely on the people who make the webbing (Dupont) for this information. They can't just make it up.

The 16.1 harness is required in most everything running quicker than 11.50 up to and including Pro Stock and even the fuel classes with the addition of a few mounting points. I would expect the standards to be more stringent for a harness expected to do its job in a 300+ MPH application. Overkill for an 11 second car? Probably. But having 1 spec, instead of multiple specs depending on ET with the resulting confusion, is OK with me. If it was a lot of money, that would be different. You can buy belts for $70.

And I have known guys who had no garage and had their race car sitting on an open trailer beside their house year round. Designers and engineers have to consider worst case situations. Sitting out in the sun in a car in south Florida year round. 300lb. dude driving his Pro Mod into the wall at 260. Any idea of the load put on the restraint system in that scenario?