What vehicle is on top of the road?
The vehicle is a bus.
    src        edge_attr  dst
0     0  to the right of   15
1     0  to the right of   14
2     1  to the right of   12
3     3   to the left of   12
4     3        on top of    9
5     3  to the right of    8
6     3  to the right of   13
7     4   to the left of    8
8     5   to the left of   14
9     6           inside   12
10    8   to the left of    3
11    8   to the left of   11
12    8  to the right of    4
13    8   to the left of   10
14   10  to the right of   13
15   10  to the right of    8
16   10   to the left of   12
17   11  to the right of    8
18   11  to the right of   13
19   11   to the left of   12
20   12  to the right of   13
21   12   to the left of    1
22   12  to the right of   10
23   12  to the right of   11
24   12        on top of    9
25   12  to the right of    3
26   13   to the left of   10
27   13   to the left of   12
28   13           beside    9
29   13   to the left of    3
30   13   to the left of   11
31   14        on top of    9
32   14  to the right of   15
33   14   to the left of    0
34   14  to the right of    5
35   15   to the left of   14
36   15   to the left of    0