Upon detecting a request for traffic information or abnormal motion, a mobile electronic device can generate and transmit a first signal to a remote traffic-information generator, the first signal identifying a location and motion of the device. The remote traffic-information generator can aggregate this type of data across devices and estimate traffic information, assuming that traffic is normal along roads not associated with first signals. The remote traffic-information generator can transmit a second signal with estimated traffic information back to the device. The conditioned transmission can allow real-time traffic information to be efficiently estimated while conserving devices' power usage and the remote traffic-information generator's processing and storage resources.