>I know that in the US the default is you can turn. Here's a little mind twister: In the US there are Right Arrow signals. A Red signal indicates you can turn

>I know that in the US the default is you can turn. Here's a little mind twister: In the US there are Right Arrow signals. A Red signal indicates you can turn right if it's safe just like ordinary Red signals. A Green signal indicates you can turn right, obviously. Wait, what? You see, this Right Arrow signal exists alongside ordinary signals at an intersection. Specifically when the ordinary signals are Green (so you can go straight ahead or turn as appropriate) but the Right Arrow signal is Red, you cannot turn right. Usually this is because someone is crossing the intersection and you would risk running them over. This specific arrangement is very rare.