Spilled cafe cup on documentsMost automakers have come out to support the new 2025 Corporate Average Fuel Economy target of 54.5 miles per gallon. Engineers, however, aren't so sure we're ready to hit that number. Despite a stamp of approval from the Union of Concerned Scientists, the folks that design and build the actual products evidentlyfeel that the CAFE target will not be hit without serious changes to vehicle size and cost.

This seems to be a case of government officials and automakers wanting to focus on three areas; cost, efficiency and safety, yet engineers believe you can only pick two. As safety demands continue to rise, cars get heavier and larger (at least until technology allows to vehicles become basically crashproof). In order to meet rising fuel economy demands, engineers would prefer to go in the opposite direction with respect to size.

Ward's Auto surveyed nearly 1,100 engineers who work for automakers and suppliers. Part of the survey involved a question regarding the ability to hit the 2025 CAFE target using the current portfolio of available materials. This question offered participants to answer using a one to five rating scale, with one being "Not at all confident" and five "Very confident." Seventy-five percent of responders answered with a three or lower.

From the engineer's point of view, it's clear that one of three parts of this triangle will need to give. We know it won't be safety, and fuel economy is a huge part of our future. Start saving now, then, because if the engineers are right, cars are about to get much more expensive.

What do you think, will automakers manage to meet CAFE 2025 goals, or will there be new legislation or penalties dished out down the road? Have your say in Comments.