Featured on Google Maps Platform: How CERTH Uses TraceMark™ Flow to Manage Traffic in Thessaloniki

Google Maps Platform sat down with our Director of Transport and Smart Cities, Oliver Looker, and Dr. Evangelos Mitsakis, Research Director at CERTH (Greece's national research and technology center), to talk about how real-time road data is changing the way transport agencies plan and respond to congestion. The full conversation is live on the Google Maps Platform blog; here's a look at what it covers and why it matters for anyone managing road networks today.

The challenge: measuring impact during major infrastructure works

CERTH's Hellenic Institute of Transport is the leading transport research body in Greece, conducting research ranging from traffic simulation models to AI-based congestion prediction. For the past two years, the team has been monitoring the Thessaloniki Flyover project, a 13.5km elevated motorway upgrade to the city's ring road, involving new tunnels and ten elevated bridges.

Projects at this scale need more than a "before and after" snapshot. CERTH needed to continuously track network performance before, during, and after construction to understand the real impact and keep citizens informed about what to expect on their commutes.

How TraceMark Flow and Roads Management Insights helped

TraceMark Flow combines Google Maps Platform's traffic and road data with the scale of Google Cloud to give planners and operators real-time and predictive intelligence, trip durations, speed intervals, origin-destination patterns, and forward-looking road conditions. Since Google's Roads Management Insights became available, that intelligence has expanded to include safety data and long-range traffic patterns, giving agencies a much fuller picture of how their networks are actually performing.

For CERTH, this meant:

• Quantifying real disruption. The team measured 40–50% increases in travel time in both directions on the ring road compared to pre-construction baselines hard numbers they could use to set public expectations.

• Tracking safety alongside speed. Alongside the travel-time impact, CERTH also identified a meaningful drop in road accidents under the new traffic conditions.

• Seeing beyond the construction zone. TraceMark Flow gave CERTH visibility not just on the ring road itself, but on major arterial routes across Thessaloniki that were absorbing diverted traffic.

• Improving short-term forecasting. The combination of real-time and predictive data sharpened CERTH's ability to spot emerging congestion and bottlenecks before they became a problem, and to route travellers toward more reliable alternatives.

Why this matters beyond one project

What stands out in this story isn't just the tooling; it's what agencies can do once they trust the data. Dr Mitsakis notes that access to high-quality, real-time traffic and travel data translated directly into better situational awareness for CERTH's team and the wider organisations responsible for managing traffic in the city, and into decisions that measurably redistributed traffic flow and reduced bottlenecks for travellers.

That's the outcome TraceMark Flow is built for: turning dense, constantly changing road data into decisions agencies can actually act on whether that's managing a single major construction project or running network-wide operations day-to-day.

Read the full Q&A with Oliver Looker and Dr Evangelos Mitsakis on the Google Maps Platform blog.