Aggregated navigation system data can be used by an artifact repository to infer the presence of a static traffic artifact. Static traffic artifact can include traffic lights, traffic signs, special traffic zones, railroad crossings, and the like. Metric data collected from multiple global positioning systems (GPS) devices can provide sampling data for inferring a static traffic artifact on a road. Metrics can include driving behavior, travel direction, velocity, timestamps, delay, and the like. For example, if thirty percent of the data collected about an intersection indicates drivers come to a stop at an intersection, the system can infer a traffic light exists at the intersection. Each traffic artifact can have an associated confidence factor which can indicate the degree of accuracy of the inferred artifact. Confidence factor can be increased or decreased based on the re-evaluation of sample data for the artifact.