Environmental Primer, Part 2: Miles Per Gallon

Using electricity as an energy source provides a finite level of power, which cannot always cover a vehicle’s power demands. The less work the vehicle has to do, the less the vehicle has to rely upon gasoline as its energy source. Low power needs are usually best in urban conditions where slow movement and idling are common. But on the highway, where higher speeds and overcoming huge amounts of air resistance are necessary, gasoline may be required for 100% of the engine’s energy needs. In this case, an efficient gasoline engine could give higher MPG than a hybrid gas-electric engine. For highway driving, an efficient gas-burning engine might be the better choice.

Of course, private cars are not the only vehicles on the road. Other kinds of vehicles operate within and between our cities, on and off the roadways, twenty-four hours a day. In the early morning, there are service vehicles owned by cities and private businesses that remove trash, maintain utilities, and fix the roadways. Tractors till the soil and cranes hoist supplies. There are delivery trucks and mail trucks moving letters, packages, produce, and goods. Police cars and services vehicles are continually on the move. Eighteen-wheelers move throughout the day and night for hundreds of miles, carrying a total load of up to 80,000 pounds. By comparison, a loaded car with four passengers and luggage is only 17–20 percent of an eighteen-wheeler’s total weight. A hybrid engine can (partially) move a car, but a truck? Almost impossible.

This is the challenge—to reduce vehicle fuel use across all types of vehicles, all types of vehicle use, and the total volume of vehicles. Improving vehicle MPG is a technological solution. Another option is reducing overall fuel usage—by simply driving less. This can be a personal choice (to walk, bike, or use mass transit where it is viable). We can also simply using products, goods, and foods that are locally produced. Those fresh fruits transported from California, Arizona, and Mexico have a cost, primarily from the gasoline used to move these products hundreds or thousands of miles.

Bettering MPG through improved technology or personal choice? Some things are simple, some are not.

[Editor’s note: this is the second in a series of articles on environmental architectural and design issues by Scott Demel, a registered architect currently practicing with Rogers Marvel in New York City, and an LEED-Accredited Professional with the United States Green Building Council (USGBC). Scott's architecture is committed to sustainable design and historic preservation. Read more about Scott and his current projects on his Web site].



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