## Monday, September 15, 2014

### Most and least fuel-efficient midsize and large car

Most and least fuel-efficient midsize and large cars

The data for this problem and the previous problem came from two EPA web sites.   The first lists the least fuel-efficient vehicle for each type of vehicle.   The second lists the most fuel-efficient vehicle in each vehicle class.

The previous problem dealt with two SUV classes.

This problem examines two automobile classes.

Question:  Below is data on the least and most fuel-efficient vehicles in two vehicle classes – Midsize Cars and Large Cars.

 Least and Most Fuel-Efficient Midsize and Large Cars Midsize Cars Least Fuel Efficient Ferrari 13 Most Fuel Efficient Ford Fusion & Toyota Prius 58 Difference 45 Large Cars Least Fuel Efficient Rolls Royce 14 Most Fuel Efficient Chevy Impala 29 Difference 15

What is the amount of reduction in gasoline consumed achieved by a 10% improvement in fuel efficiency for the least fuel-efficient vehicle in each vehicle class for a driver that travels 15,000 miles?

What is the reduction in gasoline consumed for the same amount traveled (15,000 miles) for a 10% improvement in the fuel efficiency of the most fuel-efficient vehicle in each class?

What are some of the problems limiting the effectiveness of a policy proposal to improve the fuel efficiency for the least fuel-efficient vehicle in each class?

What are some of the problems limiting the effectiveness of a policy proposal to improve the fuel efficiency for the most fuel-efficient vehicle in each class?

Answer to Math Questions: Divide 15,000 miles by current mpg to get gas consumed at current mpg.  Divide 15,000 miles by mpg x 1.10 to get gas consumption at improved fuel efficiency.    Take the difference.

 Reduction In Gas Consumption From 10%  Improvement in Fuel Efficiency Gas Consumed at Current MPG Gas Consumed at MPG 10% Higher Reduced Gas  Consumption Ferrari 1153.8 1049.0 104.9 Ford Fusion & Toyota Prius 258.6 235.1 23.5 Rolls Royce 1071.4 974.0 97.4 Chevy Impala 517.2 470.2 47.0

Policy Assessment Questions:  While the improvement in Ferrai and Rolls Royce fuel efficiency numbers would result in over 100 gallons in reduced gas consumption for each 15,000 miles driven there are not many Ferrari and Rolls drivers out there.   Targeting these few specialty cars will have little impact on overall fuel consumption on the planet.

The Prius and the Fusion are becoming popular and there is a substantial difference between fuel efficiency of these hybrids and more typical small cars.  While the reduction in gasoline consumed is limited by the fact that other options like the Corolla are more affordable the growing popularity of the Prius and the Focus is reducing the amount of gas consumed.

Interested readers should see my previous post on choice between Prius and Corolla.

The Chevy Impala is not much more fuel-efficient than other large cars including the Toyota Camry and the Honda Accord.   Both the Camry and the Accord sell more and have more power.  In fact, Toyota and Honda are able to sell more powerful only slightly less fuel efficient vehicles than GM because their overall car fleet is more fuel efficient and they more easily satisfy U.S. fuel efficiency regulations.

Interestingly, there is no large-car Hybrid at this time.     Would more stringent regulations induce car firms to build a more fuel-efficient large auto?   I don't know.  But a regulation requiring improvements in most fuel-efficicient large cars makes more sense than regulations that target scarce Ferraris and Rolls Royces.