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Trains, now on Uber. T's and C's apply. Check the Uber app.

This is scientific American 60 second science.

I'm Christopher Intagata.

When you walk on a sandy beach, it takes more energy than striding down a sidewalk, because the weight

of your body pushes into the sand. Turns out, same thing is true for vehicles driving on roads.

The weight of the vehicles creates a very shallow indentation or you know deflection in the

pavement and it makes it such that it's continuously driving up a very shallow hill.

Jeremy Gregory, a sustainability scientist at MIT.

His team modeled how much energy could be saved

and greenhouse gases avoided by simply hardening the nation's roads and highways.

And they found that stiffening 10% of the nation's roads every year could prevent 440 megatons

of carbon dioxide equivalent emissions over the next five decades.

That's enough to offset half a percent of projected transportation sector emissions

over that same time period.

To put those emissions savings into context, that amount is equivalent to how much

CO2 you'd spare the planet by keeping a billion barrels of oil in the ground, or by growing

7 billion trees for a decade.

The results are in the transportation research record.

As for how to stiffen those roads,

Gregory says you could mix small amounts of synthetic fibers or carbon nanotubes into paving materials, or you could

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