In an exemplary method, a traffic monitoring subsystem receives mobile device attribute data from a plurality of mobile devices over a network, selectively aggregates the mobile device attribute data, the selectively aggregating including identifying anomalous data in the mobile device attribute data and excluding the anomalous data from the aggregated mobile device attribute data, and generating traffic condition data based at least in part on the aggregated mobile device attribute data, the traffic condition data representative of a traffic condition. In certain examples, the traffic monitoring system provides the traffic condition data to at least one of the mobile devices.