What is on the road?
The truck is on the road.
    src        edge_attr  dst
0     2      in front of    9
1     3  to the right of    6
2     3  to the right of    8
3     4   to the left of    7
4     6  to the right of    8
5     6   to the left of    3
6     7  to the right of    4
7     8   to the left of    6
8     8   to the left of    3
9     8   to the left of    9
10    9               on    1
11    9  to the right of    8
12    9           behind    2