What vehicle is gray, the bus or the car?
The car is gray.
    src        edge_attr  dst
0     0   to the left of    3
1     0   to the left of    7
2     1   to the left of   19
3     1           behind   15
4     3   to the left of    9
5     3  to the right of    0
6     4  to the right of   16
7     4   to the left of    6
8     4  to the right of   15
9     4  to the right of   10
10    6  to the right of    4
11    6  to the right of   15
12    6  to the right of   10
13    6  to the right of   16
14    7   to the left of   19
15    7               on   18
16    7  to the right of    0
17    8               of    0
18    9  to the right of    3
19    9   to the left of   19
20   10   to the left of    4
21   10   to the left of    6
22   10  to the right of   16
23   11   to the left of   14
24   11  to the right of   15
25   11               on   12
26   12           behind   15
27   14   to the left of   20
28   14  to the right of   15
29   14  to the right of   11
30   14               on   12
31   15      in front of   12
32   15   to the left of   20
33   15   to the left of    4
34   15   to the left of   17
35   15   to the left of   14
36   15   to the left of   11
37   15   to the left of    6
38   15      in front of    1
39   16   to the left of   21
40   16   to the left of    4
41   16   to the left of   10
42   16   to the left of    6
43   17  to the right of   15
44   17               on   12
45   19  to the right of    9
46   19               on   18
47   19  to the right of    1
48   19  to the right of    7
49   20               on   12
50   20  to the right of   15
51   20  to the right of   14
52   21   on the side of    1
53   21  to the right of   16