What is the vehicle that the trees are behind of?
The vehicle is a van.
    src        edge_attr  dst
0     0   to the left of   20
1     1      in front of   17
2     1   to the left of   18
3     1   to the left of   20
4     1      in front of   19
..  ...              ...  ...
66   20  to the right of   14
67   20  to the right of   13
68   20  to the right of    3
69   20  to the right of    1
70   20  to the right of    0

[71 rows x 3 columns]