Who is riding?
The motorcyclist is riding.
    src        edge_attr  dst
0     0  to the right of    8
1     1               on    7
2     2  to the right of    7
3     4          wearing    0
4     4           riding    3
5     4               on    3
6     6  to the right of   10
7     7   to the left of    2
8     8   to the left of    0
9     9   to the left of   14
10    9  to the right of   11
11   10   to the left of    6
12   11   to the left of    9
13   12               on    3
14   13   to the left of   14
15   14  to the right of    9
16   14  to the right of   13