The fuel efficiency of the vehicle can be calculated as such:

This equation gives us the energy converted to forward motion per gallon of gas. We can use this value to determine the percent of total fuel energy that is devoted to forward motion:

From these calculations, we can determine that 25% of the energy from a gallon of gas is converted to actual forward motion of the vehicle, giving us a fuel efficiency value of 25%.

All of the answers are part of energy conservation. But to be net zero the building has to produce energy and cannot be using any more than it produces. 

CAFE is a standard enacted by U.S. Congress in 1975 with the objective to improve fuel economy for all vehicles produced for sale in the U.S. The acronym stands for Corporate Average Fuel Economy, because it applies to automotive corporations marketing cars in the U.S. and the objective was to improve average fuel economy.

CAFE is an ever-increasing average fuel economy standard that automobile manufacturers must satisfy in order to market their fleet of vehicles in the United States. This regulation is targeted toward new vehicles.

Example: Current CAFE standards mandate a manufacturer's fleet average  miles per gallon in fuel economy. If a car company produces three cars, rated at 35, 30 and 20 mpg, average fuel economy would be determined as:

Based upon their average fleet fuel economy, this car company could now sell their vehicles in the United States for the 2015 model year.

The fuel economy standards established by CAFE are more strict and demand more fuel efficiency for passenger cars than for light trucks. Passenger cars are defined as having a Gross Vehicle Weight Rating (GVWR) of less than 8500 lbs, while a light truck is a vehicle with a GVWR greater than 8500 lbs. The light truck classification was initially for utility and commercial vehicles, but since many SUVs exceed the GVWR rating for a passenger car, they are regulated separately from the fleet of passenger cars and are not subject to stringent fuel economy standards.

First we want to determine the difference in minimum fuel economy standards and the actual fuel economy of Company A's fleet:

Given that Company A's fleet is out of compliance by and they have sold passenger cars in U.S. markets, we can calculate the fine as such:

Therefore, the total penalties for Company A totals for the entire fleet.

Light trucks, such as diesel trucks and SUVs, are covered by CAFE standards, as well as cars. Semis, however, are not regulated by this legislature.

We aren't quite to 40 miles per gallon yet, but 2011 was the first year that CAFE regulations set the standard for over 30 miles per gallon. The standard from 1990 up to 2011 was just over 27 miles per gallon, still a vast improvement from 1978's 18 miles per gallon.