ARTICLE: MIT engineers rules stiffer roads save fuel

**ghosthunter** · July 31st, 2012 03:47 PM

MIT engineers rules stiffer roads save fuel
Words by Niky Tamayo | Source: Massachusetts Institute of Technology News

A recent study by Civil Engineers at the Massachusetts Institute of Technology (MIT) has, for the first time, mathematically modeled the effects of road surface on fuel economy. For anyone who's ever gone jogging or cycling, the results aren't terribly shocking: softer roads waste more fuel.

Other studies have traced the effects of surface roughness on fuel economy, but this is the first time that the flexibility of the actual road surface has been modeled. The results of this study could have far-reaching implications for the way we build and repair roads.

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SOURCE: Kotse.com

**niky** · July 31st, 2012 04:40 PM

Makes sense if you're a jogger. Softer surfaces, like rubber mat or dirt, absorb energy and force you to work harder to move forward. Harder surfaces are easier to move on faster.

Apparently, cars are so heavy that even asphalt or thin concrete is "soft" to them.

**uls** · July 31st, 2012 04:58 PM

steel rails rule!

**niky** · July 31st, 2012 05:13 PM

Originally Posted by uls

steel rails rule!

There's a reason trains use steel...

...of course, it's crap hard to brake on... though the problem in terms of brakes for most trains also has something to do with the fact that they weight a kajillion tons.

**oj88** · July 31st, 2012 05:46 PM

True, but I'm sure that a lot of motorists would still prefer driving on smooth blacktops rather than on hard concrete, even if it means spending a tiny bit more on gas. The former is also easier on the suspension.

With thousands of miles of interstate highways, the effect of road hardness on fuel economy would probably be more significant in countries like the US.

**kinyo** · July 31st, 2012 09:06 PM

isn't this similar to saying stiffer tires save fuel? less rolling friction?

**niky** · August 1st, 2012 03:42 PM

Originally Posted by oj88

True, but I'm sure that a lot of motorists would still prefer driving on smooth blacktops rather than on hard concrete, even if it means spending a tiny bit more on gas. The former is also easier on the suspension.

With thousands of miles of interstate highways, the effect of road hardness on fuel economy would probably be more significant in countries like the US.

Well... concrete isn't necessarily harsher than asphalt. At least, as long as there are no bumps, it's not easily noticeable.

And asphalt is a pain in the ass. Melts in the rain too easily... as motor oils and solvents mix into it.