Which kind of vehicle is to the left of the people?
The vehicle is a van.
    src        edge_attr  dst
0     0   to the left of    7
1     0  to the right of    1
2     0  to the right of   12
3     1  to the right of   12
4     1   to the left of    7
5     1   to the left of    0
6     2   to the left of    9
7     2   to the left of    6
8     3               on    4
9     3   to the left of   11
10    4   to the left of   11
11    4   to the left of    5
12    5  to the right of    4
13    5               on   11
14    5               on   10
15    6  to the right of    8
16    6  to the right of    2
17    7       walking on   10
18    7  to the right of    1
19    7  to the right of    0
20    8   to the left of    6
21    9  to the right of    2
22   11  to the right of    4
23   11  to the right of    3
24   12   to the left of    0
25   12   to the left of    1