Participation and Security – Perceived Safety on the Street

Feeling safe in public spaces is essential to our quality of life. Sensafety shows how safe people feel on the street and anyone interested can use this free, simple app to indicate whether they feel safe where they are. Your smartphone automatically detects your location, and the information you provide appears immediately on a map to answer the following questions: Where and when do most participants feel safe? What influence do time of year and time of day have? Dr. Sandro Rodriguez Garzon of T-Labs and TU Berlin tells us how the app started as a small student project and developed into the extensive research project "Citizen Science Initiative Sensafety" with many facets and stakeholder groups.

Dr. Rodriguez Garzon, how did you come up with Sensafety?

I came up with the idea while traveling through Colombia, Mexico and South Africa. Whether I was able to travel safely often depended on which region, place, district, part of town or even street section I visited. The time of day – darkness or daylight – also played a major role. The risk was not just crime, but also being involved in a traffic accident or having an accident on an unpaved hiking trail.

Crime and accident statistics help assess risk, but they say little about whether it also feels safe on the ground. I benefited from my own experience and, above all, talking to locals or other travelers. That's how I came up with the idea of having everyone on site record their perceived safety using an app and widely sharing the aggregated results with time and location details.

What's the purpose of this app?

Most users want to see when and where people feel safe or at risk in public spaces. We want to look at perceived safety from different angles. For local authorities and neighborhood centers, the project helps identify spaces in the city where people experience fear. For urban planners, traffic planners and urban sociologists, it shows how such spaces can be prevented through urban planning or security policies.

Our department investigates how mobile participation technologies can be implemented so that residents, visitors, tourists, local businesses ؘ– in short, anyone who's in the public space – can use them. We are also examining how to technically evaluate the data.

Who do you want to reach and who actually takes part?

Of course, we would prefer to reach everyone. The app is used anonymously and doesn't collect demographic data. Previous projects with a similar design and objective failed, because too few users actively collected data. Reasons often included app usability and/or mandatory collection of personal data during registration. With Sensafety, we are trying a different approach and "buying" higher participation at the price of less meaningful data, since we don't require users to register and have kept the app simple and intuitive.

We haven't yet done a separate survey on user demographics, so we don't know which type of user is behind a rating. The data doesn't show us any information on age groups, for example. However, we do approach people directly at local festivals or events to involve different participants. We also can't guarantee that the map covers all areas, since each user decides when and where to rate a location. So far, voluntary feedback from users indicates that the app appeals especially to women.

How do you integrate citizen knowledge into Sensafety?

Anyone can participate in the great Sensafety "experiment" in any public place and at any time by giving a personal rating. We can evaluate the statistics independently, in near real-time. We are also planning a research cooperation with a major German city, where citizens will be asked to use Sensafety to rate their subjective feeling of safety before and after urban development measures. The citizens can also select one or more influencing factors from a location-specific list. At a neighborhood festival, people of different origins and ages were asked what actually influences their perceived neighborhood safety. The results of this survey were added to a list of influencing factors.


What does the Sensafety data tell you about perceived safety?

We haven't yet systematically analyzed the data. A first look leads us to believe that if users feel unsafe in a larger area, it's mostly related to the fear of falling victim to crime. On the other hand, if users feel unsafe in a specific spot on an intersection, it probably has to do with the fear of being the victim of a traffic accident. However, these are only hypotheses and need to be confirmed through data analysis and representative surveys. We still need solid evidence for these initial findings.


Interviewer: Christina Camier


For more information and to download the app, visit the website Citizen Science Initiative Sensafety:




Sandro Rodriguez Garzon

Organization name Service Centric Networking