What kind of vehicle is behind the trailer?
The vehicle is a van.
    src        edge_attr  dst
0     0  to the right of   14
1     0  to the right of   12
2     1   to the left of   12
3     1  to the right of    9
4     1   to the left of   14
5     1  to the right of    7
6     2  to the right of   11
7     2  to the right of   10
8     2   to the left of    5
9     4   to the left of   13
10    4   to the left of    8
11    5   to the left of   13
12    5  to the right of   10
13    5       hanging on    4
14    5   to the left of    8
15    5  to the right of    2
16    6  to the right of    7
17    7   to the left of    1
18    7   to the left of    6
19    7   to the left of   12
20    8  to the right of    4
21    8  to the right of    5
22    9   to the left of    1
23    9   to the left of   12
24   10   to the left of   14
25   10   to the left of   12
26   10   to the left of    5
27   10   to the left of    2
28   11   to the left of   12
29   11   to the left of    2
30   12  to the right of   10
31   12  to the right of   11
32   12  to the right of    1
33   12   to the left of    0
34   12      in front of   14
35   12   to the left of   14
36   12  to the right of    7
37   12  to the right of    9
38   13  to the right of    4
39   13  to the right of    5
40   14  to the right of    1
41   14   to the left of    0
42   14  to the right of   12
43   14  to the right of   10
44   14        parked on    3
45   14           behind   12