The next time you are at the front of the lineup waiting for the signal to turn green, watch the driver beside you. Many times when the traffic signal turns green they will immediately proceed without looking to the left or right for hazards or traffic already lawfully in the intersection. A green light doesn't always mean go.
There are three situations where drivers facing a green light must not proceed immediately. Most people already follow these three exceptions, but failing to take them into account can cause confusion or a crash.
The first of the three is a situation where turning direction controls are in place. The driver may only proceed as indicated by these signals.
The second is where there is a pedestrian lawfully in the intersection or adjacent crosswalk at the time the signal is green. Drivers must yield to these pedestrians.
The final situation is where a vehicle has entered the intersection waiting to turn and has been unable to do so before the signal goes red. Cross traffic on the new green signal must yield right of way to allow the first vehicle to clear the intersection.
As usual I concur but would like to suggest one other good reason to exercise caution upon the green light; depending on the location, there are more and more people that accelerate on amber and actually run red lights. Taking a split second to check for red light runners could save your life or the life of a loved one. Most T-Bone accidents that occur due to red light runners can be extremely serious for the struck car. So pardon me as I take an extra half second to look for red light runners.
Here's another one: "Sneak-a-lefties"
Some drivers in the on-coming lane will try to beat the on-coming traffic and a make a left turn in-front of the pack.
Happened in the first accident I was involved in (as a passenger), our vehicle was coming up to a red light, travelling in the right lane, no cars at the stop line; light turned green and our driver proceeded to keep momentum ~25km/h and drove into the intersection, immediately colliding with an on-coming left turner who gunned it in-front of the opposing traffic.
Lots of damage to my friends brand new car, good thing we had a Police cruiser following us not far behind - he saw the entire thing and made a testimony to ICBC as to what really happened.