After the meeting with local municipalities in Palazzo Medici Riccardi, we left the sample #0 of VehicleCounter working from the windows overlooking Via Cavour. It is a very central street in Florence, that runs from Piazza del Duomo, at the very heart of the city, to the boundary of the historical center. This is how it looks from the windows of Palazzo Medici Riccardi:
In the picture, as seen by our VehicleCounter, Piazza del Duomo is placed on the right, so the white car (a local taxi) is outbound from the historical center. Being so close to the inner city center, the traffic in Via Cavour is limited to public transportation, neighborhood inhabitants and a few other allowed categories of vehicles.
We have set up two probes, one for each direction. “Probe 0” is the probe the counts vehicles coming from the right side of the image (as the white car in the picture, i.e. outbound from the historical center), while “Probe 1” is the probe counting vehicles that moves in the opposite direction (inbound the historical center). After a couple of days, we made a first check to see how VehicleCounter #0 was working, and we found something very interesting.
In the pictures below you can see the length distribution of vehicles detected by the two probes:
By comparing the two diagrams, we can see that there is a local maximum in the plot from Probe 0, corresponding to a length of 10-11 meters, that does not appear in the plot from Probe 1. From our experience, it is unusual to see such different distributions in the lanes of the same road, so we thought that could be due to a misconfiguration. But on the other hand, the distributions in the range [0; 8] meters look extremely similar, and that usually means that the probes are configured correctly. So, if we assume that VehicleCounter is correctly configured and no other strange event has occurred, the only explanation we could give is that full-sized buses (which have a max length of 12 meters by law), only travel outbound from the city center. If so, probe 1 would not see any bus.
We did not know if that could be a reasonable explanation, so we asked people from Città Metropolitana to comment these data. Can you guess what they said? :-) (hint: give a look at comments below and on our page on Facebook…)