Mainers’ personal location data, scraped from cellphone apps and other devices, will be used by state and local governments to analyze traffic and plan highway projects. But it is also prompting privacy concerns.

Four state and local transportation agencies recently purchased a subscription to San Francisco-based Streetlight Data for detailed data on traffic flows, congestion, trip origin and destination, even pedestrian and cyclist movement.

Information gleaned from trillions of records collected by voluntary location-based service apps on GPS-equipped smartphones, vehicles and devices is organized by Streetlight Data into aggregated, anonymous patterns. The company says its information includes no personal or identifying information. Streetlight estimates it can track an average sample of 23 percent of adults in vehicles and on foot and 12 percent of commercial trucks on the road.

Even with assurances the data is completely anonymous, having access to so many locations is unsettling to Peter Mills, executive director of the Maine Turnpike Authority. The authority is the lead agency on the contract with Streetlight.

Mills’ first question when presented with the product was how it protected privacy.

“The minute you open one of those apps up, it gives the world the GPS location of your phone and it is accurate to a few feet,” he said. “That phone of yours is being tracked all day long, probably several times over, depending on what apps you have on.”


Mills said he intends to watch closely how the software is used, and if it looks like personal data is vulnerable, the agency will take steps to fix it.

But if the platform works like they hope it will, changes to transportation planning will be significant, Mills said.

That so much location data is swept up when users authorize a smartphone app like those for dating, weather, shopping and fitness to track their location with GPS should not be a revelation, said Streetlight Data founder and CEO  Laura Schewel.

“I would be surprised if people were still surprised this much data is being collected by their phone,” she said.

Other companies measure congestion, but Streetlight adds local traffic data and census information to fill out details like income level and residence. That added information layer gives planners insight into transportation behavior so they can track trends such as ride-sharing, identify reasons behind traffic buildup at an intersection, and determine whether carpooling or shuttles could ease rush hour traffic, Schewel said.

“You need a persistent data system to really understand those kind of things,” Schewel said. “Being data-driven to solve the transportation infrastructure challenge, that is at the core of what we do.”


Even if the goal is better and more accurate transportation planning, products like Streetlight are part of a larger unregulated marketplace where personal data is harvested, manipulated and sold, said Kade Crockford, director of the Technology for Liberty program at the American Civil Liberties Union of Massachusetts. Data collection may be voluntary, but most people don’t read or fully comprehend dense, legally complicated use agreements when they download an app, she said.

“We in the United States basically have no existing statutory or regulatory protections against companies harvesting our location information and turning around and doing whatever they want with it.”

Crockford is skeptical that location data can be made completely anonymous. Public employees might not know how to match available data back to private individuals, but someone might be able to, she said.

“Transportation planning is certainly important and I can understand why the Maine Department of Transportation would want access to this information, but it is critical they have policies in place so that any of this information is not abused,” Crockford said.

The Maine Turnpike Authority, Maine Department of Transportation, city of Portland and Portland Area Comprehensive Transportation System teamed up to buy a $371,400 yearlong subscription. The turnpike authority will contribute $131,390, Maine DOT $125,000, Portland $90,000 and PACTS $25,000.

Up to 25 other agencies can access the program under the subscription. It provides data in a 35-mile corridor on either side of the turnpike south of Augusta, encompassing most of southern Maine.


Right now, traffic engineers depend on limited, incomplete data collected from surveys and daily traffic counts to research problem areas and make infrastructure plans, said state traffic engineer Steve Landry. The origin and destination mapping Streetlight Data promises – following trips from start to end – offers comprehensive and accurate information the department can’t get now.

“When we talk about where people go, we depend on models and models are our best guess at where traffic is going to go,” Landry said. “This is going to allow us to actually see where traffic went.”

Streetlight can provide data down to the neighborhood level. Staff in cities such as Portland will be able to examine a single street or intersection and see where people are going and coming from, where pedestrians and cyclists are and the busiest times of the day.

And that data is constantly updated and only five months old, much more accurate than traditional data collection, said Portland Public Works Director Chris Branch.

“It is an incredibly good, very detailed data set we have never had the ability to get before,” Branch said.

Portland intends to start using the program within the month, initially to examine the traffic patterns on Commercial Street for an upcoming study about mobility and congestion on the busy thoroughfare.


At least 400 agencies and companies now subscribe to Streetlight Data, including big clients like the Virginia and Ohio departments of transportation.

Ohio planners have used the platform extensively since it subscribed two years ago, said Scott Phinney, administrator of statewide planning and research at the state transportation department.

In one instance, officials used movement data to link backups onto an interstate highway near Cincinnati to a mistimed traffic signal, saving the state from building a $12 million interchange expansion, Phinney said. Canton, Ohio, used the data to find out how full its municipal parking lots were ahead of an expansion of the Pro Football Hall of Fame, and the state plans to identify harmful delays at railroad crossings and gauge the need for sidewalks and bike lanes.

“Data-driven decisions are critical,” Phinney said. “We don’t want to make decisions based on opinion, we want to make it on data.”

Since the data is anonymous and aggregated to remove any identifying traces, Phinney said it is appropriate to use for transportation planning. Plus, unscrupulous users are prevented from using Streetlight software to track down an individual.

“They will not let you zoom into someone’s house or business and snoop on people; they try very much to protect the privacy of people’s lives,” he said. “This is a tool to help us make our highway system work better, so it is easier to get to jobs, to school, for freight to move through our system.”

Peter McGuire can be contacted at 791-6369 or at:

Twitter: PeterL_McGuire

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