What is the name of this vehicles?
These are trucks.
    src        edge_attr  dst
0     1   to the left of    4
1     1  to the right of    3
2     1  to the right of    5
3     2  to the right of    5
4     3               on    5
5     3   to the left of    1
6     4               on    2
7     4  to the right of    1
8     5   to the left of    2
9     5   to the left of    1
10    5   to the left of    6
11    6  to the right of    5