Hosting the World Cup, GDOT Built Its Own Traffic Index With RITIS

When the FIFA World Cup brought eight matches to Atlanta, the Georgia Department of Transportation (GDOT) needed to answer two questions objectively: was traffic getting into the venue performing acceptably, and when was it actually over? GDOT’s old cue, watching parking decks clear, broke down because FIFA controlled several decks and used them differently than a typical event. With no off-the-shelf metric that fit, GDOT built its own index using RITIS connected-vehicle probe speed data, comparing real-time conditions against historical norms for the exact same routes, days, and times.

The result was two custom metrics. TWIZLI (Temporally Weighted Index for Zonal-Level Ingress) uses RITIS historical speed profiles to set an event-day benchmark, up to 50% slower than normal, then measures the percentage of five-minute intervals each route met that benchmark on match day. TWIZLE (Temporally Weighted Index for Zonal-Level Egress) does the same for the trip home, using RITIS data from around halftime as a “new normal” baseline, since downtown Atlanta still had FanFest and other activity going on. GDOT considered egress complete once about two-thirds of monitored routes, tracked live in RITIS, recovered to that benchmark and held steady.

Building a custom index like this only works with probe data that’s granular enough for a route-specific historical baseline and fast enough to compare against in near real time. Across the matches, GDOT reported ingress conditions met or exceeded benchmark roughly 68% of the time, giving leadership a defensible number instead of “traffic seemed bad for a couple of hours.” Because the method only requires defining routes and pulling the matching RITIS data, GDOT reused it for Houston, another World Cup host city, and plans to keep using it for future events, including the next Super Bowl.

“A tool like RITIS … was extremely valuable throughout this process. All of this information was feeding reports that went not only to GDOT executive leadership, but to Atlanta if they wanted to see it, and as we understand it, was being fed directly to FIFA in certain ways.”
— Justin Hatch, Assistant State Traffic Engineer, Georgia DOT