Are there either cars or buses?
No, there are no cars or buses.
     src        edge_attr  dst
0      0   to the left of   18
1      0   to the left of    1
2      1  to the right of    0
3      1  to the right of   19
4      1   to the left of    9
..   ...              ...  ...
152   21   to the left of   18
153   21  to the right of   19
154   21  to the right of   20
155   21   to the left of    1
156   21  to the right of    2

[157 rows x 3 columns]