Skip to Content
Streetsblog USA home
Streetsblog USA home
Log In
Safety

What Can an Algorithm Tell Us About How People Perceive Streets?

4:06 PM EDT on August 8, 2014

This map of perceived safety of New York City streets capes was developed using an algorithm by researchers at MIT. Click to use the interactive map.
This map of perceived safety of New York City streetscapes was created using an algorithm developed by researchers at MIT. Click to use the interactive map.
This map of perceived safety of New York City streets capes was developed using an algorithm by researchers at MIT. Click to use the interactive map.

What makes people feel that a street is safe, and what do those perceptions tell us about different streets? A group of researchers at MIT have developed a formula designed to approximate people's subjective reactions to the way streets look. They hope it will help chart shifts in the quality of city environments over time and prove useful to urban planners and architects seeking to better understand what makes streets appealing.

Based on survey responses from almost 8,000 people, the research team developed an algorithm they are using to rank the perceived safety of every streetscape image provided by Google Maps in New York, Boston, Chicago and Detroit. Using the algorithm enables the MIT researchers to rate many more streets than if they had relied on human surveys. They hope to eventually make maps like the one above available in every city in the Northeast and Midwest. They call the tool Streetscore.

The MIT team says their algorithm is a reliable mimic of how humans perceive visual cues in urban environments. Using a 1 to 10 scale, 84 percent of the time it can successfully predict whether real people will rate a street on the low end (less than 4.5) or the high end (more than 5.5). The factors incorporated by the algorithm are not public at this time.

The perception of "safety" that Streetscore approximates is defined vaguely, since the survey doesn't explicitly distinguish between traffic violence and violent crime. But the researchers say they have found a correlation between homicide rates and Streetscore ratings in New York. Meanwhile, a look at the New York City map reveals that some streets with high rates of traffic injuries and fatalities, like Queens Boulevard, rate poorly, while others, like the leafier Ocean Parkway in Brooklyn, rate well. Industrial zones and streets under elevated highways stand out as some of the lowest-scoring streets in New York.

The researchers note in their report [PDF] that "suburban houses with manicured lawns and streets lined with trees" tend to score highly. However, the New York City map shows that several extremely dense urban streets, such as Manhattan avenues, also get very high scores.

Here's how a random sample of streets ranked, on a scale of 1 to 10, 10 being the safest.

Image: Streetscore
Image: Streetscore
Image: Streetscore

You can contribute to the project and help improve the tool's accuracy by evaluating street images in an online survey.

Stay in touch

Sign up for our free newsletter

More from Streetsblog USA

Monday’s Headlines Like Stadiums Without Parking

The lack of parking at Kansas City's new soccer stadium is a feature, not a bug. Plus other news.

February 26, 2024

Should Communities That Suppress Housing Lose Their Road Funding?

A Colorado bill would require sprawling cities to take action to increase their affordable housing supply before they collect money to build more roads — and some want to take it national.

February 26, 2024

Why ‘Safe Systems’ Are Not Enough to End Road Violence

Two years into the National Roadway Safety Strategy, why hasn't America made more progress towards Vision Zero?

February 26, 2024

Friday’s Headlines Are So Fresh and So Clean

The only thing Americans love more than a car is a clean car.

February 23, 2024

CalBike: Tell the Legislature Hands Off Active Transportation Funding

Calbike has an action alert that allows its members to write directly to legislators with their feelings on whether or not the ATP funding should be restored before the legislature votes on the budget in June.

February 22, 2024
See all posts