Question

The US consumer fleet (cars, SUV’s, vans, cross-overs and light trucks) has an average drag coefficient of 0.4, an average miles driven per year of 12,500 at 50 MPH and an average frontal area of 5.5 m2. Being that there are 265 million of these ‘average’ vehicles on the road driven by consumers, calculate:

a. Gasoline consumed per vehicle annually assuming 25% overall efficiency

b. Gasoline consumed per vehicle annually assuming if the speed limit on federal highways was cut down from 70 to 55 MPH resulting in a decrease in the average speed to 43 MPH.

c. How many barrels of oil would be saved annually by lowering the speed limit?

d. If instead of 55 MPH there were an absolute federal speed limit on all roads of 45 MPH, lowering the average speed to 35 MPH, repeat b) and c) above.

e. If instead of lowering the speed limit the aerodynamics of all vehicles were improved such that the average vehicle now has a drag coefficient of 0.35, how many barrels of oil would that save annually?

f. If the size of engines were cut down on every vehicle in the fleet equivalent to the efficiency of the average vehicle above increasing to 40%, how many barrels of oil would that save annually?

g. What if by force of tax we were all limited in driving a certain number of miles and this resulted in the original average vehicle driving 10,000 miles per year, how many barrels of oil would that save annually? How many gallons of gas is that per capita and how much would each person save dollar-wise per year?

Answer 1