Are there any traffic lights or helmets?
Yes, there is a traffic light.
    src        edge_attr  dst
0     0   on the side of    7
1     0   to the left of   11
2     1     connected to    4
3     1  to the right of    7
4     1  to the right of    3
5     1   to the left of    8
6     2  to the right of    7
7     2   to the left of    8
8     3   to the left of   11
9     3  to the right of    4
10    3   to the left of    1
11    4   to the left of   11
12    4   on the side of    7
13    4   to the left of    3
14    5   to the left of    8
15    5  to the right of    7
16    5   on the side of    7
17    6               on    7
18    6   on the side of    7
19    6   to the left of   11
20    7   to the left of   10
21    7   to the left of   11
22    7   to the left of    5
23    7   to the left of    2
24    7   to the left of    1
25    8   to the left of    9
26    8      attached to   11
27    8  to the right of    2
28    8  to the right of    1
29    8  to the right of    5
30    8   on the side of    7
31    9  to the right of    8
32    9   on the side of   11
33   10   on the side of    7
34   10  to the right of    7
35   11  to the right of    6
36   11  to the right of    7
37   11  to the right of    3
38   11  to the right of    0
39   11  to the right of    4