Clean Diesel: Greener Than the Prius?
By Todd Kaho
Depending on the type of driving you do most, you may find that some clean diesel cars deliver better fuel economy than traditionally efficient gas cars, and that they are even competitive with gasoline-electric hybrids, such as the Toyota Prius.
To see how clean diesel stacked up, I compared the diesel Volkswagen Jetta TDI with the Toyota Prius and the Ford Focus. Clean diesel and hybrid cars don’t get the best mpg estimates from the Environmental Protection Agency’s tests. Know that your mileage will vary based on your driving habits and conditions, but with both the Jetta and the Prius, it is possible to beat the official figures.
In my test of the Jetta — which is eligible for a federal tax credit of up to $1,300 — I was able to average in the mid-40s for city mpg and more than 50 mpg on the highway, without much effort. The Prius had the upper hand in city driving, with about 51 to 52 mpg, but only 47 mpg on the highway. Then there’s the traditionally efficient and affordable Ford Focus, which achieved a respectable 26 mpg in the city and 35 mpg on the highway.
| | 2010 Volkswagen Jetta TDI | 2010 Toyota Prius III | 2010 Ford Focus SEL |
Engine | 2.0-liter, 4-cylinder, diesel | 1.8-liter, 4-cylinder, gas-electric | 2.0-liter, 4-cylinder, gas |
| Transmission | 6-speed automatic | automatic | 4-speed automatic |
| Base price | $24,510 | $24,150 | $19,180 |
| EPA city/highway mpg | 30/42 | 51/48 | 24/34 |
| Real-world mpg estimate | 47 | 49 | 30 |
| Range at highway mpg | 559 miles | 521 miles | 409 miles |
| Fuel capacity | 14.5 gallons | 11.9 gallons | 13.5 gallons |
| Annual fuel cost | $1,235 | $801 | $1,430 |
| Powertrain longevity | 5 | 4 | 3.5 |
| Interior room | 91 cubic feet | 93.7 cubic feet | 93.4 cubic feet |
| Seating | 5 | 5 | 5 |
| Air Pollution score | 6 | 9.5 | 7 |
| Greenhouse Gas score | 8 | 10 | 8 |
| Drive score | 5 | 3 | 4 |
Base price: Manufacturer’s suggested retail price + destination fee
Annual fuel cost: Based on 45 percent highway, 55 percent city driving, 15,000 annual miles, with diesel fuel price = $2.80 per gallon, gasoline = $2.67 per gallon
Powertrain longevity: 1 = worst, 5 = best
Air Pollution score: Zero = most tailpipe emissions, 10 = least
Greenhouse Gas score: Zero = most greenhouse gas emissions, 10 = least
Drive score: 1 = worst, 5 = best (based on overall operating experience: fun to drive, acceleration, cornering and braking)
Find out more about clean diesel vehicles, including how they work and which automakers offer them, in Clean Diesel: A New Era of Green Cars.
