Show notes
Bus timetables, tree surveys, pothole reports. Civic technologist Marcus Bell explains how public data quietly powers the apps we use every day — and why so much of it is still locked in PDFs.
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If you've ever checked when the next bus is due, looked up whether a park has a public toilet or reported a broken streetlight through an app, you've probably used open data without realising it. Cities and public bodies around the world publish enormous amounts of information about themselves. A surprising amount of everyday technology depends on it.
Marcus Bell has spent his career at the point where public data meets public use. He has worked inside local government, at a civic technology nonprofit and as a consultant to transport agencies. In this episode, he explains what open data is, why it matters and why, despite years of progress, so much of it remains frustratingly hard to use.
In this episode
- 00:00 — The bus timetable that changed everything
- 05:40 — What "open data" actually means
- 12:20 — The apps you use that depend on it
- 20:55 — PDFs, spreadsheets and the format problem
- 28:30 — Privacy: what should never be published
- 35:10 — How residents can push for better data
- 40:45 — Marcus's favourite civic projects
What counts as open
Marcus defines open data simply: information that anyone can access, use and share, in a format a computer can read, under a licence that permits reuse. Each part of that definition matters. Data that's technically public but published only as scanned PDFs is, in practice, almost as closed as data that's kept secret.
"A PDF of a spreadsheet is a photograph of a spreadsheet," he says. "You can look at it. You can't use it."
"Public data that nobody can use isn't open. It's just visible."
The transport revolution
Public transport is Marcus's favourite example of open data at work. Many transport agencies now publish timetables and, increasingly, real-time vehicle locations in standard, machine-readable formats. That has allowed independent developers and large mapping companies alike to build journey planners, accessibility tools and live departure boards — often far more quickly than agencies could build them alone.
The lesson, he argues, is that governments don't need to build every app themselves. They need to publish good, reliable data and let others build on it.
The privacy line
Daniel pushes Marcus on the risks. Isn't there a danger that publishing more data exposes people? Marcus agrees that the line matters enormously. Aggregated information — how many trees there are on a street, how often a bus route runs late — is generally safe and useful. Information that could identify individuals, or reveal patterns about vulnerable people, should be handled with great care or not published at all.
"Openness is a default," he says. "It isn't an absolute. Good open data programmes spend as much time deciding what not to publish as what to release."
What residents can do
Marcus's advice for listeners who want better data where they live:
- Find out whether your city or region has an open data portal. Many do.
- If something you need isn't there, ask for it — politely and specifically.
- Report errors when you find them. Data improves when people use it.
- Support local civic technology groups, which often run volunteer projects built on public data.
Key takeaways
- Open means usable. Data has to be accessible, machine-readable and licensed for reuse. A scanned PDF doesn't count.
- You already depend on it. Journey planners, live departure boards and many local apps are built on data published by public bodies.
- Governments don't have to build every app. Publishing good, reliable data lets others build tools faster than agencies could alone.
- Unexpected uses are the point. A city tree survey became shady walking routes, allergy maps and lessons for schoolchildren.
- Privacy draws the line. Aggregated information is usually safe and useful; anything that could identify individuals needs great care or shouldn't be published.
- Residents can push for better data. Find your local portal, ask for what's missing, report errors and support civic technology groups.
- Data improves with use. The more people rely on a dataset, the more pressure there is to keep it accurate and up to date.
Transcript excerpt
Daniel: What's the most unexpectedly useful dataset you've seen published?
Marcus: A city tree survey. Every street tree, its species, its size. People used it to plan shady walking routes in summer, to map allergy hotspots, to teach kids about trees. Nobody imagined those uses when it was released. That's the point of open data — you don't have to imagine them.
About our guest
Marcus Bell is a civic technologist who has worked inside local government, at a nonprofit building digital tools for public services and as an independent consultant to transport agencies. He has helped several cities launch and improve their open data portals, and he co-organises a monthly volunteer evening where residents, developers and council officers build small projects together. He describes his job as "translating between people who have the data and people who need it." He has strong opinions about bus timetables.
Credits
Signal is hosted by Maya Chen and Daniel Osei. Maya returns next week.