A town introduced a digital map showing vacant parking spaces. Officials expected drivers to spend less time searching, since the map would direct them to an available place before they entered a crowded street.
(A) The team therefore changed what the map displayed. Instead of announcing a precise number of empty spaces, it showed how recently each area had been checked and warned users when information was old. Drivers could then judge the uncertainty before deciding where to go.
(B) During the first week, however, drivers reported that spaces marked as vacant were already occupied when they arrived. The map had been accurate when it was updated, but several minutes could pass before the next update. More drivers following the same signal made the delay even more important.
(C) Once these limitations became visible, users stopped treating the display as a promise. The map did not create additional parking, but it helped them make decisions with a clearer understanding of what the information could and could not tell them.