> What I mean by that is if the most cost effective big rig truck gets say 10MPG then that cost gets built into the market rate. If a new truck design gets 15MPG and costs more you can figure out the costs vs what's out on the market and see if it's an improvement.

I see your point, but that's a particularly poor example. Most shippers will pass the fuel costs as a "fuel surcharge" on to the customer. If you're an owner/operator, this is the most lucrative part of the business, and is really the whole reason to be an O&O in the first place. Trucking is just a really strange business.