With Streetchange, a team of researchers at the renowned Massachusetts Institute of Technology (MIT) has put together a fascinating online mapping project as a web app. Their new method measures the change and transformation of single streets and entire neighborhoods.

The key question tackled by the Streetchange scientists: How safe do people feel in a certain area? To get around the subjective nature of human judgement and perception, the Streetchange web app relies on an impartial algorithm.

To this end, the researchers compared Google Street View images from 2007 and 2014, compiling a total of 1.6 million blocks in Baltimore, Boston, Detroit, NYC, and Washington, D. C., into an interactive map.

Their stated mission: to identify how these blocks have changed over the period of seven years. Has urban development been mostly positive? And how safe do (primarily) pedestrians feel in the areas covered by the study?

A laptop screen shotws Manhattan as seen in Streetchange
Manhattan as seen in Streetchange.
Photo: Streetchange (the image has been modified)

A Streetscore algorithm simulates perceived safety

This is where the specially developed Streetscore measuring unit comes into play. The algorithm devised by MIT scientists simulates human safety perception based on visual analyses to provide researchers with an objective, calculable measurement. Pursuing this particular path, they wanted to produce reliable data and establish how a city like Baltimore has developed and changed over time.

Streetscore measurements and factors cover a wide range of different aspects, from traffic-specific characteristics like street width or pavements to parameters like population density, darkness at night, or just how safe people feel from hold-ups and other types of criminal assault.

A laptop screen shows the changes through different coloring of sectors
The darker the sectors, the more change is happening.
Photo: Streetchange (the image has been modified)

Visualizing urban change

For decades, urban planners, economists, sociologists, and architects have been discussing why certain cities and neighborhoods change for the better while others are subject to vacancies and decay.

Besides known success factors like attractive jobs, affordable rents, nearby shopping options, and sufficient green spaces this study could add a further determining index to the mix: objectively measurable safety perception as a general urban planning and development marker.

Meanwhile, the Streetchange project has already revealed some good news: The majority of the 1.6 million surveyed inner-city blocks on the US East Coast have improved their Streetscore between 2007 and 2014.

Click here for more information on Streetchange.