Emission reductions slowed down by heavier and more powerful cars

Over the last thirty years cars sold in Sweden have become larger, and what's more they accelerate ever faster. This has entailed that some of the cars' technical improvements have not led to lower fuel use.

If cars had not become larger and accelerated faster between 1985 and 2007, they would have required 47 percent less fuel. Instead, the actual reduction during the period has been 18 percent.

While interest in environmentally friendly cars has indeed increased in recent years, instead of a shift toward smaller cars with less horsepower, there has been a rise in the number of diesel and ethanol cars. This has led to reduced carbon-dioxide emissions, but more measures are needed to make full use of the potential we have to rein in emissions.

These findings are being presented by Frances Sprei at Chalmers University of Technology in Gothenburg, Sweden, who has spent several years researching developments in newly sold cars in Sweden. Now she is putting forward these new figures in her doctoral dissertation.

"Measures that may lower emissions involve using policy instruments that reduce fuel consumption per se, regardless of fuel type," says Frances Sprei.

Her dissertation is titled "Energy Efficiency Versus Gains in Consumer Amenities" and was publicly defended on September 6 at Chalmers University of Technology in Gothenburg.