When stopped behind another vehicle you need to have a least 1 car length between you and the car in front. This is so that if you were rear ended, you would not get pushed into the car in front and also because if you realized you were about to get hit from behind, you might be able to escape. A rough way to estimate this is that you should be able to see the ground behind their rear tires. Only one car is allowed in the intersection on a left turn. This is so that the intersection does not get blocked, in case an emergency vehicle etc. had to pass through. You must stay behind the stop line and wait for the other car to turn. You must also wait with your wheels straight. Again, if you were rear ended and had you wheels turned, you would be pushed into the oncoming traffic. It would also prevent you from escaping straight ahead or to the right. Improper left turns are dangerous and would be marked severely. Entering an intersection on an amber or red light would be cause for failure by a DriveTest Examiner