Traffic lights - red and green

Rule: At regulated crossings, stop at a red light, go on a green light.

Traffic logic: Heavy traffic crossings need regulation, as the rule for unregulated crossings is not sufficient to ensure safe and smooth flow. As you know, a green light indicates go, red means stop. Never cross the stop line if the light is red, as you may cause a crash.

If there is a single light for both straight and right, it is possible for opposing traffic to be "go" at the same time (illogical, but it does happen; these kinds of signals used to be very common a few decades ago, but thankfully less so nowadays). In such cases, traffic turning right should wait for straight traffic from the opposite side to clear the crossing first. Usually, there are separate lights for straight and right.

Driving tips: Most left turns are "free". However, in heavy traffic, wait for straight traffic from your right (if any) to clear the crossing before you turn left ("give way" to traffic on your right). Always check for signs that left is not free, especially on unfamiliar turns.