What is the passenger on, a bus or a train?
The passenger is on a bus.
    src        edge_attr  dst
0     0  to the right of    5
1     0   to the left of   15
2     0  to the right of   12
3     1               on   20
4     1  to the right of   15
..  ...              ...  ...
64   25  to the right of   21
65   25  to the right of   17
66   25   to the left of   19
67   25   to the left of   11
68   25  to the right of   14

[69 rows x 3 columns]