In the age of Covid-19 someone should write a social distancing app. For example: Ping GPS data, available for every smartphone to report when people come close together too often or use bluetooth. GPS data is accurate to within four meters. Generally, bluetooth broadcasts a maximum of between 15 and 78 meters depending upon several factors. The app could record when it encounters another smartphone within certain distances, when and for how long was the encounter. Over time, a log file would be recorded. Statistics would be established for what constitutes good social distancing using these stats. An ideal application for this app might be a construction site or golf course.
If a golf course were 35 acres and was occupied by 250 people, as they spread out over the course there might be an average of 4 contacts per person at any one time. 250 x 4 = 1000 contacts. The app, registering a number higher than 1000, suggests a wider social distancing may be required. An alert is displayed: CONGESTION.