An impression estimation system for estimating visual impressions of a plurality of vehicles configured with exterior graphic messaging. A mobile device application of each of a plurality of mobile devices associated with the plurality of vehicles generates vehicle mobility data. A computational platform includes a processor and program code which, when executed by the processor, causes the processor to, with respect to each vehicle of the plurality of vehicles: (i) identify, using the vehicle mobility data, one or more of the road segments in which the vehicle was present; (ii) estimate, using the traffic volume data, a number of potential visual impressions of the vehicle within the road segments; (iii) determine an estimated number of visual impressions; (iv) generate visual impression information based at least in part upon the estimated number of visual impressions; and (v) cause display of the visual impression information.