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Changing the way Boston paves streets could cool the city and reduce greenhouse gas emissions, MIT researchers say

MIT News reports on a study done on Boston and Phoenix that found that changing our traditional dark asphalt road surfaces to something lighter could reduce the urban "heat island" effect and in turn reduce local greenhouse emissions.

The researchers reported that, at least in Boston, switching to lighter, stiffer and smoother surfaces, such as concrete made with light-colored binders, could reduce overall temperatures by as much as 3 degrees and mean less greenhouse-gas emissions both by reducing the energy vehicles need to traverse the road and by reducing the need for cooling in neighboring buildings. Such savings are possible in part based on how much of our land surface is covered by asphalt.

The researchers emphasized, though, that it's not as easy as just replacing all the asphalt with concrete because in some spots, that could increase air-conditioning costs in buildings that have a lot of that sunlight reflected from the roads onto them. Also, unlike in Phoenix, cooling in the winter is not what we want to see in Boston, so the right pavement would have to be selected on a block by block basis, they say.

Achieving these savings, however, requires that cool pavement strategies be selected according to the climate, traffic, and building configurations of each neighborhood.

They add that the cladding on buildings could also be part of the strategy to reflect the sun's energy back into space rather than along the ground.

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I tweeted a photo a few days ago from Seaver Street, where we doubled the width of the street and lost a bunch of trees at the same time. The color of pavement might help a bit, but reducing the amount might make more of a difference, except that our current culture is generally more asphalt = good.

We have all sorts of overly-wide streets in Boston, many of which are vestiges of the not-fully-built highway system and many of which absorb and radiate heat unnecessarily. Like Warren and MLK Boulevard in Roxbury. Or Rutherford Ave in Charlestown. Or Comm Ave in Brighton. If we had some gumption, we'd start looking at places where we have way too much pavement and ask not how we can make the pavement a different color, but why we have so much in the first place.

Then if you want you can get really creative, for instance, Eugene, Oregon has bus lanes with grass between the tire tracks. Much of Europe has green, grassy tram tracks (hello, Comm Ave?).

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There is a lot of evidence that narrower roads also force drivers to slow down which Boston desperately needs.

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South Boston pioneered a win-win situation long ago, double parking.

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If we don't let dipshits from Norwood speed through West Roxbury to visit their aunts who still live in the neighborhood, then the community will be destroyed within weeks.

- West Roxbury road diet opponents

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If we're going to put grass in the roads, we have to find something other than salt to de-ice roads with. Or we have to plant crabgrass.

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Plenty to choose from - also popular in areas with "tidal flooding".

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Asking for Julia Mejia!

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It will reduce road violence.

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Interesting but it seems expensive to implement, plus concrete fabrication is also responsible for lots of emission.

There are easier and cheaper solutions. For instance we could start taxing asphalt per the square foot to get people to think about having less of it. Exiting the train station on the Charles St side in Fields Corner, one walks past multiple houses that are 90 to 100% surrounded by asphalt. It's as ugly and harmful as unnecessary and there are plenty of houses like this all over the neighborhood.

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so there are a number of reasons to get rid of paved surfaces.

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Cambridge is currently testing something similar on one parking lot in Inman Square.

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Here's a comparison of asphalt and concrete for road surfaces. Excerpt:

3. How climate affects which road type you need

Temperature changes, the impact of the sun’s heat, snow and ice, and rain, all can take a heavy toll on roadways.


*Asphalt’s black color absorbs the sun and facilitates snow and ice melt. If the sun can’t reach the surface, it’s okay to apply salt because chemicals won’t damage asphalt.

*Asphalt road provides better safety of the vehicle against snow and skidding. The reason is that its surface isn’t as rigid, allowing it to expand and contract depending on the climate.

*Asphalt can soften and crack over time as it is exposed to moisture and sunlight. As water percolates into the asphalt, it widens the cracks leading to distorted and unattractive surfaces.


*Cold weather can cause concrete to expand and contract, leading to cracking.

*Concrete can also be damaged by road salt. Salt damages concrete over time by causing corrosion to occur under the surface, causing cracking and crumbling.

*Finally, concrete is slippery when icy or rainy providing poor vehicle traction.

Maybe concrete isn't the best choice for New England.

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There are some concrete roads around here, mostly in Brookline. I think part of Rt. 16 in Newton is Concrete too.

In one sense they seem to hold up better with fewer potholes. But edges move relative to one another forming large spaces of non-continuous roadway. When they do utility work, it gets filled in with asphalt leaving a channel which can be nerve-racking to ride a bike in since it would be easy to go down when transiting between that and the larger roadway.

I always assumed the concrete roads were a failed test since there are so few of them.

More trees would be the better solution. Too bad the current thinking is to replace them with small, ornamental types that provide little shade.

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to dirt roads or gravel covered roads. I know my little side street in the city could survive without a paved road. This would also slow down traffic. There's a section of Centre St. in Newon Center that is concrete. Has anyone asked Newton how that stretch of roadway holds up?

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Last time I went down Centre they had changed a huge chunk of it to asphalt.

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