Is this a traffic sign or a traffic light?
This is a traffic light.
    src        edge_attr  dst
0     0   to the left of   12
1     0   to the left of    5
2     0   to the left of    4
3     0   to the left of    1
4     0   to the left of    6
5     0   to the left of    9
6     0   to the left of    3
7     1  to the right of    0
8     1  to the right of   15
9     1  to the right of   14
10    1  to the right of   18
11    3  to the right of    0
12    4  to the right of    0
13    4  to the right of    9
14    4  to the right of    6
15    5  to the right of   12
16    5  to the right of    0
17    6   to the left of    4
18    6  to the right of    0
19    8  to the right of   14
20    9  to the right of    0
21    9   to the left of    4
22   10  to the right of   11
23   11   to the left of   10
24   12  to the right of    0
25   12   to the left of    5
26   14   to the left of    1
27   14   to the left of    8
28   15               on   18
29   15   to the left of    1
30   18   to the left of    1