Each year on 24th June Florence celebrate its patron saints festival (Saint John) with the usual fireworks show (the so-called “fochi di San Giovanni”). It is a very old tradition, loved and awaited by many Florentines, that each year overcrowd squares, boulevards and riversides of the city to look (and criticize, as the tradition requires - “l’eran meglio quelli d’anno!”) “i fochi”.
The fireworks show is so popular that it is not uncommon for people coming from the suburbs of the city or from nearby towns to find themselves stuck in the traffic, and when the show begins, many people just turn off the engine and drop off his car in the middle of the street to enjoy the show (usually causing the complaints of other drivers, but that is another story…).
But how strong is the call of “fochi di San Giovanni”? Will it be visible from the point of view of a traffic sensor in the suburbs of the city? Well, yes! It is. Look at these plots.
These data come from a traffic sensor placed in Via Reginaldo Giuliani, a two-lane street often traffic-congested that links Florence to the nearby town of Sesto Fiorentino. The plot above shows the inbound traffic flow, while the plot below shows the outbound traffic flow. As you can see, there is an unusual increase of the inbound traffic flow that starts around 08:30 PM and lasts till about 10:00 PM, exactly when the fireworks show begins! Then, we see an increase in the outbound traffic flow starting around 11:00 PM, with a duration that is comparable with that of previous “burst” of inbound traffic.