The invention concerns a traffic information device comprising a portable one-way messaging receiver (10), designed to provide motorists with information concerning running times in a road network, said receiver comprising a keyboard (12) and a screen (11). The receiver memory contains, for each road network section, a starting point, an arrival point and an elementary running time. Moreover, the central unit is adapted to update the elementary running times of the sections on the basis of received radio messages, and to compute and display the global running time between a starting point and an arrival point as required, based on the stored elementary running times.