What kind of vehicle is driving on the bridge?
The vehicle is a truck.
    src        edge_attr  dst
0     0  to the right of    7
1     1  to the right of   12
2     1  to the right of    8
3     1  to the right of    6
4     2  to the right of   10
5     2      in front of    8
6     3   to the left of   12
7     4             near   10
8     4  to the right of    7
9     4  to the right of   10
10    6   to the left of    1
11    6  to the right of   11
12    6   to the left of    8
13    7   to the left of    4
14    7   to the left of    0
15    8   to the left of    1
16    8  to the right of    6
17    8  to the right of   12
18    8           behind    2
19    9               on   13
20   10   to the left of    2
21   10   to the left of    4
22   10             near    4
23   11   to the left of   12
24   11         crossing    2
25   11   to the left of    6
26   12   to the left of    1
27   12       driving on    2
28   12  to the right of   11
29   12   to the left of    8
30   12  to the right of    3