In automobile design, there is a trade-off between efficiency, horsepower and mass (safety) that manufacturers must deal with in coming up with their new car designs each year. The Obama Administration, however, has seized decision-making from auto manufacturers and their consumers when it chose to increase the Corporate Average Fuel Economy (CAFE) standard to 54.5 miles per gallon by 2025, about twice its current level. The problem with this huge increase in CAFE is that we can only go so far in achieving this increase without affecting driver and passenger safety due to weight reductions.

The Process to Increase Automobile Efficiency

Automobile manufacturers employ various engine technologies to obtain improved efficiency, including direct-injection combustion, variable valve timing, sophisticated air management including turbo-charging, and fine-tuning engines with sophisticated sensors and algorithms. All of these processes are used by the industry to meet current CAFE standards. Automobile manufacturers also evaluate transmission processes to help save fuel by allowing the engine to run at lower revolutions per minute (rpm). Some of today’s vehicles employ as many as 8 gears that automatically maintain engine rpm within a certain range; far from the original 2-gear automatic transmissions.

However, engine and transmission modifications cannot achieve a 54.5 mile per gallon average vehicle efficiency without reducing car weight significantly.[i] Obviously, it takes less energy to propel a lighter car at a particular speed than a heavier car. In the past, automobile manufacturers reduced weight by removing the spare tire, making thinner glass components such as windshields and employing plastic in vehicle design.

But weight reduction also can mean less safety. For instance, a Dodge Ram pick-up in a head-on collision with a Ford Focus would surely be the winner, i.e. the Dodge Ram owner would walk away with minor injuries while the Ford Focus driver may not survive the crash. Bigger and heavier is better when it comes to car accidents as many a soccer Mom knows since they choose SUVs to haul their children to and from school functions.

The Insurance Institute for Highway Safety (IIHS) ran a series of tests in which it pitted a smaller vehicle against the next size larger vehicle from the same manufacturer. Specifically, they ran a Honda Fit into a Honda Accord, a Toyota Yaris into a Toyota Camry, and a Mercedes C Class into a Smart Fortwo (owned by Mercedes). In 40 mph offset-collision tests, the small cars were basically obliterated by the larger models.

Of course, the industry has improved safety by installing air bags, using high-tech materials like carbon fiber, and employing seat belts. But these initiatives can only do so much. While traffic fatalities had reached the lowest level in more than six decades in 2011, in the first nine months of 2012, traffic deaths increased 7.1 percent compared to last year’s figures, which is the largest increase for that calendar period since the National Highway Traffic Safety Administration began keeping records in 1975.[ii] And, in fact, it reversed a downward trend that had continued for 6 years.[iii] The historical six-year decline in the fatality rate is believed to be due to improvements like safer vehicles and roads; more effective laws such as graduated driver licensing laws that govern teenage driving; better technology such as  electronic stability control; and awareness efforts that, among other things, have led to increased use of seat belts.

Technological innovations such as electronic stability control, anti-lock brakes, and air bags may have reduced the number of fatalities. But, none the less, it is clear that smaller vehicles forced on the public by the federal government to increase efficiency cannot compete against larger vehicles in crashes.  Mass is key to safety, all things being equal.

Horse Power, Vehicle Weight and the American Public

It is no surprise to automobile manufacturers that the American public has historically preferred greater horse power and more weight than increased efficiency in its vehicle purchases. To evaluate this, Christopher Knittel, a professor of applied economics at the M.I.T. Sloan School of Management, determined that if weight, horsepower and torque were held to their 1980 levels, and efficiency-boosting technologies were employed, fuel economy for both passenger cars and light trucks would have increased by almost 60 percent from 1980 to 2006. That means, instead of an average fuel economy of 23 miles per gallon across the fleet, fuel economy would have reached about 37 miles per gallon. The actual fuel economy gain during that period, however, was only 15 percent.[iv]

According to Mr. Knittel, the addition of robust safety equipment to vehicles caused some of the weight gain, but changing preferences among consumers was a greater contributor to the lower increase in fuel economy. For example, in 1980, 18 percent of new cars sold in the United States were light trucks, but by 2004, the percentage of those vehicles freely chosen by consumers was 60 percent. As a result, horse power doubled and weight increased by 30 percent over that time period.


The Obama Administration has determined that the average new car fuel efficiency must meet 54.5 miles per gallon by 2025, regardless of what that means to horse power, vehicle weight and mass, and passenger safety. While we do not have the data that indicates the number of fatalities that have occurred because of the push for lighter and more environmentally friendly cars, we do know that the public has chosen performance and weight (and likely safety) over fuel economy in the past. Plus, now we see that the number of automobile fatalities grew in 2012. The federal government, however, has decided that the preferences of the American public are no longer relevant and that a doubling of new car fuel economy must occur by 2025. The total cost of that decision for drivers and their passengers is unknown.

[i] National Review, Our Cars’ Weight Problem, January 8, 2013,

[ii][ii] Auto Blog, U.S. traffic deaths climb 7.1% in first 9 months of 2012, December 21, 2012,

[iii][iii] New York Times, After Six Years of Decline, Traffic Deaths Begin to Inch Upward, October 4, 2012,

[iv] New York Times, How Weight and Horse Power Nullify Gains in Efficiency, January 4, 2012,

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