Which kind of vehicle drives down the ground?
The vehicle is a fire truck.
    src        edge_attr  dst
0     1  to the right of   16
1     2   to the left of    9
2     3   to the left of    7
3     3  to the right of   13
4     4  to the right of   11
5     5          wearing    4
6     5  to the right of   10
7     5       walking on   14
8     5  to the right of   11
9     5  to the right of   17
10    7  to the right of   13
11    7  to the right of   11
12    7  to the right of    3
13    8  to the right of   16
14    8  to the right of   12
15    9  to the right of    2
16    9   to the left of   15
17   10   to the left of    5
18   10  to the right of   11
19   11   to the left of   10
20   11   to the left of   14
21   11  to the right of   12
22   11   to the left of    7
23   11     driving down    6
24   11   to the left of    4
25   11   to the left of    5
26   12   to the left of   16
27   12   to the left of   11
28   12   to the left of    8
29   13   to the left of    3
30   13   to the left of    7
31   14  to the right of   11
32   15  to the right of    9
33   16   to the left of    1
34   16   to the left of    8
35   16  to the right of   12
36   17          wearing   10
37   17   to the left of    5