Is there any black traffic signal or street sign?
No, there is a street sign but it is white.
    src        edge_attr  dst
0     0  to the right of    1
1     0      in front of    5
2     1   to the left of    8
3     1   to the left of    0
4     1   to the left of    7
5     1   to the left of    5
6     2  to the right of    5
7     3   to the left of   11
8     3           beside   15
9     3             near   15
10    3   to the left of    8
11    3          next to   15
12    4   to the left of   14
13    4   to the left of   13
14    5           behind    0
15    5  to the right of    1
16    5               on   16
17    5   to the left of    2
18    7  to the right of    1
19    8  to the right of    1
20    8  to the right of    3
21   10               in    6
22   11  to the right of    3
23   13  to the right of    4
24   14  to the right of    4
25   15             near    3