Which kind of vehicle is it?
The vehicle is a bus.
    src        edge_attr  dst
0     1  to the right of    5
1     1  to the right of    3
2     3   to the left of    7
3     3   to the left of    5
4     3   to the left of    1
5     4  to the right of    5
6     5   to the left of    1
7     5   to the left of    4
8     5  to the right of    3
9     5   to the left of    8
10    5   to the left of    7
11    6  to the right of    8
12    7  to the right of    5
13    7  to the right of    3
14    8   to the left of    6
15    8  to the right of    5