Are there either any buses or cars?
Yes, there is a bus.
     src        edge_attr  dst
0      0  to the right of   17
1      0  to the right of   13
2      0  to the right of   39
3      0  to the right of   23
4      0  to the right of   45
..   ...              ...  ...
253   44   to the left of    6
254   45  to the right of   24
255   45   to the left of    0
256   45   to the left of   41
257   45  to the right of   38

[258 rows x 3 columns]