Use Python to plot the vehicle count between two consecutive intersections

# this is part of a research project in which we are estimating the real time vehicle count on a road segment

# this preliminary result is produced by processing vehicle count data from loop detectors embedded under two consecutive intersections

# we studied three consecutive links (i.e., in total four sets of detectors included)

# the time frame for the data is 0700~0800, Dec 01~31, 2008

# the vehicle count(T) = vehicle count(T-1) + upstream detector count - downstream detector count [1]

Figure 1: vehicle counts on each link during weekdays

Figure 2: vehicle counts on each link during weekends

The vehicle counts, as one may noticed, are sometimes negative.

This is because, as in [1], we don't have data on the vehicle count(T-1). It is assumed to be 0.

The consequent of this assumption is that, the ploted figures (could be also taken as the distribution), are shifted figures from the original real data. One can add a base on X to reconstruct the real situiation, as long as the base is well estimated/measured.