Road
surface roughness was something that I'd been aware of for some time,but what caught my attention about this study was that road
stiffness matters. It's not just that the surface of the paving material itself is deflecting, but that the whole pavement is deflecting as your vehicle rolls over it. For example. it you were driving on a 1/2" thick plate of steel, the steel wouldn't compact or be rough, but it would bend as you roll over it, setting up a "wave" in front of you. Here's another excerpt:
Quote:
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By modeling the physical forces at work when a rubber tire rolls over pavement, the study’s authors, Professor Franz-Josef Ulm and Ph.D. student Mehdi Akbarian, conclude that because of the way energy is dissipated, the maximum deflection of the load is behind the path of travel. This process has the effect of making the tires on the vehicle drive continuously up a slight slope, which increases fuel use.
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