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