Finding the Route of Least Emissions

Experts are working on models that would bring green-routing to your GPS

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Reuters

Google Maps has an assortment of settings for your trip-navigation needs. You can get from Point A to Point B in a car, on a bus, by foot or on a bike. You can get there avoiding highways or toll roads. You can even get there counting in kilometers instead of miles, if you want to travel like a European.

But no mainstream navigation service has yet mastered the holy grail of environmentally conscious travel – the route of least emissions.

Researchers at a handful of universities across the country are at work on this concept, called green routing. The idea sounds pretty straight-forward: Instead of selecting the shortest route to the grocery store, you would be able to pick the path with the smallest carbon footprint. Researchers suspect that on the aggregate, if large numbers of us were adjusting our driving patterns like this every day, it would have a serious impact.

A recent study from researchers at SUNY-Buffalo found that rerouting just a fifth of drivers in a computer simulation of traffic in the Buffalo area could reduce regional auto emissions by 20 percent.

Designing such a system, though, is much more complicated than the idea itself sounds.

“Sometimes, it’s true the greenest route would not be the fastest route,” says Adel Sadek, one of the researchers at SUNY-Buffalo who has been working on this, as part of a program funded by the Department of Transportation’s Intelligent Transportation System Joint Program Office. “You’d save energy and reduce emissions, but you’d get to the destination a bit later than if you followed the shortest path.”

This is because most green routes funnel drivers from highways to surface roads. In Sadek's modeling, the delay wouldn’t be that long (the green route in the Buffalo region is only about 11 percent longer on average). How much of a delay, though, would people put up with to be green? And what would happen if large numbers of people started driving this way at the same time?

“Another issue we're looking at,” Sadek says, “is if everybody starts following the green path, that green path is not going to be the green path any longer because of the congestion.”

For all of this to work, designers need to take into account the entire system of a city’s moving traffic, so that at any moment, cars would be in some kind of green-routing equilibrium. And live data on route emissions and traffic patterns is only now enabling researchers to figure out how all this might come together in an application in your car.

If they can figure it out, a lot of people who can’t afford a hybrid might be able to get in on eco-conscious driving.

"The key advantage to green routing is that it’s something you could implement right away," Sadek says. "The other strategies are typically much longer-term, much more costly. This idea, many people now use GPS navigation devices, so if we change the objective and we have the models and information needed to figure out the greenest route, that’s something we could implement right away."

How close, though, are we to be being able to implement this right away?

"I don’t think we’re that far," Sadek predicts.

Photo credit: Supri Supri/Reuters

About the Author

  • Emily Badger is a former staff writer at CityLab. Her work has previously appeared in Pacific StandardGOODThe Christian Science Monitor, and The New York Times. She lives in the Washington, D.C. area.