What vehicle is black?
The vehicle is a bus.
    src        edge_attr  dst
0     0   to the left of    1
1     1               on    3
2     1             near    4
3     1             near    3
4     1  to the right of    0
5     1  to the right of    2
6     1   to the left of    4
7     1  to the right of    5
8     2     walking down    5
9     2   to the left of    1
10    3             near    4
11    3  to the right of    5
12    3             near    1
13    4             near    1
14    4  to the right of    1
15    4             near    3
16    5   to the left of    3
17    5   to the left of    1