Case Study: Georgia Department of Transportation achieves smoother traffic flow and reduced congestion with Teradata Variable Speed Limit Analytics

Georgia DOT Variable Speed Limit Analytics Help Solve Traffic Congestion

Georgia DOT partnered with Teradata to evaluate a Variable Speed Limit (VSL) pilot on the northern half of I‑285 in Atlanta. GDOT’s challenge was to quantify the customer service, safety and efficiency benefits of VSLs—measuring how changing, electronic speed limits affect speeds, slowdowns and driver behavior—using large, high-resolution traffic data.

Teradata analyzed more than 133 million minute-by-minute INRIX speed records, created analytic definitions for persistent slowdowns, bottlenecks and “turbulence,” and measured deceleration in the zones upstream of queues. In the first 90 days of VSL operation they observed measurable reductions in speed turbulence (average zone turbulence fell from 20.8 to 18.9 mph/min and total turbulence declined about 10%), indicating smoother, more gradual speed reductions and indicating improved traffic flow and potential safety benefits.

Georgia Department of Transportation

Mark Demidovich

Assistant Traffic Engineer