If you live in New York City, there's a good chance that easy access to public transit makes your carbon footprint a lot lower than people in other U.S. cities. But that doesn't mean New Yorkers never get in cars: Each year, yellow cabs in the city take over 150 million trips. Researchers at the MIT Senseable City Lab have mapped out every single trip from 2011 on a new interactive website that shows how many of those trips could have been shared—saving riders cash and reducing massive amounts of pollution.
"We found that the majority of trips could be shared," says Michael Szell, a postdoc researcher at the lab. "There are a lot of redundant trips—at least in Manhattan, it happens that more people in the same place want to take a trip at the same time to the same destination." In total, if passengers were willing to go just three minutes out of their way, 40% of the trips could have been eliminated.
Since taxis already have tracking devices onboard, it wouldn’t be hard to hook passengers up with someone going in the same direction. "The only thing that would be needed is some kind of smartphone app," says Szell. You'd also need a tiny bit of patience: After telling the app where you want to go, you would wait up to a minute for the system to search all nearby riders to find a match.
Even if the technological hurdles are minimal, it would likely take a while before a citywide system could be implemented. "Policymakers need to be convinced that this might be a good idea, and then the taxi union—all of these political actors that need to work together somehow," Szell says. "And of course people don’t necessarily like to sit next to a stranger. So one would have to implement this as smoothly as possible."
Surprisingly, even if only a fraction of people were actually willing to share rides—just 10%—Szell says the system will still be able to match most of them up with someone else, saving a large number of rides.
And though the system might seem like it's uniquely suited for Manhattan, it's actually likely to work elsewhere. The team at MIT is currently testing the same approach in Boston, Vienna, and some Chinese cities. "We only have preliminary results, but it seems that this could work for all kinds of cities, not just New York," Szell says.