Which of the following would NOT be considered a common source of en-route information?

The reasoning behind identifying personal communications devices as not a common source of en-route information lies in the nature of how information is disseminated and utilized by travelers on roadways.

Common sources of en-route information are typically those that provide traffic updates, road conditions, or advisories in real-time to a broad audience. Highway advisory radio serves this purpose well by broadcasting important messages to drivers. Variable speed limits are integrated technology on highways aimed at managing traffic flow, ensuring that speed guidelines are adjusted based on real-time conditions. Commercial radio and TV often include traffic reports, weather updates, and other relevant information for drivers, making them reliable sources for en-route data.

On the other hand, personal communications devices such as smartphones can be used to receive information, but they are not inherently sources of en-route information themselves. They require apps or user-directed searches to access information rather than providing it directly like the other sources listed. Therefore, while personal devices can facilitate the receipt of information, they do not serve the same common purpose of actively broadcasting it to all roadside travelers in a standard manner.