Mobility technologies are reshaping how people move. Innovations like car-sharing apps and e-scooters unlocked with smartphones are making transport more efficient. They can also have a positive environmental impact, by discouraging vehicle ownership and reducing emissions.

For these technologies to be improved and evaluated by city transport officials, access to data about people’s movements around a city is needed. City officials need to be able to check that mobility data is accurate and complete. But current solutions involve the sharing of raw data.

This compromises people’s privacy and security, even when identifying details are removed. For example, the fitness app Strava made anonymised location data openly available - and accidentally revealed the locations of secret U.S. military bases.

The Strava heatmap that unintentionally leaked the location of US bases.

There are ways to draw insights from mobility data whilst protecting privacy, but that will require a new approach.

Privacy must inform every part of the design process

The National Association of City Transportation Officials (NACTO), is working on what role cities should play in managing mobility data. I recently spoke to NACTO on this topic alongside Kevin Webb, Co-Director of SharedStreets, which develops open tools for transport data. We have been working together to think through what needs to change, based on our shared values that:

  • Privacy shouldn’t be a luxury; data should be kept private as a default
  • Technologies should be designed to be publicly accountable, understood and regulated

These issues can’t be seen as an afterthought or add-on for technologies that use data. They must be approached as a core design constraint, informing every aspect of the digital architecture from UX design to the technical stack.

Tools like Trillian can add accountability and transparency

New tools will be part of the answer. Google’s open-source software Trillian offers some interesting possibilities; it converts sensitive data into cryptographic hashes that can be used to create digital proofs. These proofs can be used to verify that data hasn’t been covertly added or altered, without exposing underlying sensitive data. Trillian can also be used to verify that certain data points are either present or absent in a database.

Hashes can help show when data has been changed. Even when the source data changes slightly, its hash will change significantly. David Marques/IF: CC-BY

We’ve written more about Trillian in previous posts. In the context of mobility data, Trillian could be used to prove that a dataset is complete, while at the same time protecting privacy and enabling all parties to be accountable.

Specific permissions, rather than openly available data

Once data is stored and shared in this way, the right permissions can allow specific people and groups to access certain data. This could include city officials, app developers, transport system employees, users of mobility apps, and even designated data representatives or civil society groups.

What should the permissions structure look like for city data? Sarah Gold/IF: CC-BY

This kind of permissions structure should let people access data that organisations hold about them. Information should be easy and intuitive to access, and give people the power to spot when something isn’t right, to give them more agency to affect change.

Cities can lead the way on ethical data practices

A fight for this type of data access is already underway. Four Uber drivers are suing the company for access to data about their journeys that they claim they are entitled to under GDPR. This data would help them check if they are receiving the right pay and holiday allowance.

Log data could be used in this context to allow drivers to access their work history, and hold their employers to account. Sarah Gold/IF: CC-BY

As this example shows, tech companies are failing to take the lead in setting standards for ethical data use, even as they claim that they’re taking privacy more seriously. City officials are in a position to make impactful decisions about data use, from WiFi on the Underground to the personal information linked to travelcards. They have the potential to become leaders in this space and define standards that become widely adopted.

Digital services that make cities smarter are a good thing but it’s not necessary to sacrifice individual privacy to make this happen. With the right tools and design, services can be built that are trusted, efficient, useful and secure. It’s possible to draw powerful insights from data that helps make services better without putting people’s safety at risk.


Thanks to Kevin Webb, Jess Holland, Grace Annan-Callcott and Ella Fitzsimmons for their contributions to this post