Stiffer road surface implies reduced fuel consumption

Credit - MIT

Study by civil engineers at MIT has revealed that building stiffer road surfaces can bring down the vehicle fuel consumption by as much as 3%.
This 3% would amount to a massive reduction in CO2 emission as well as savings worth billions of dollars of crude oil.

Professor Franz-Josef Ulm and PhD student Mehdi Akbarian of the civil engineering department at MIT have successfully shown the deflection under the tires is similar to that of beach sand underfoot: With each step, the foot tamps down the sand from heel to toe, requiring the pedestrian to expend more energy than when walking on a hard surface.

On the roadways, even a 1 percent increase in aggregate fuel consumption leaves a substantial environmental footprint. Stiffer pavements — which can be achieved by improving the material properties or increasing the thickness of the asphalt layers, switching to a concrete layer or asphalt-concrete composite structures, or changing the thickness or composition of the sublayers of the road — would decrease deflection and reduce that footprint.

“We’re wasting fuel unnecessarily because pavement design has been based solely on minimizing initial costs more than performance — how well the pavement holds up — when it should also take into account the environmental footprint of pavements based on variations in external conditions,” Akbarian says. “We can now include environmental impacts, pavement performance and — eventually — a cost model to optimize pavement design and obtain the lowest cost and lowest environmental impact with the best structural performance.”

For more information - http://web.mit.edu/press/2012/pavement-savings-tires.html