Blind Spots
Keep in mind, BEFORE you make change into an unoccupied lane, you must follow a specific set of actions. Make this a habit for safely changing lanes.
First, check rear-view and side mirrors
Second, signal your intention to change lanes/zones.
Third, look over your shoulder on the side you intend to turn. This checks your blind spots, areas in which you cannot see.
Fourth, when you can safely do so, execute your move.
Fifth, position yourself in the lane/zone by slowing down or speeding up to match the normal traffic flow or speed limit.
Keep in mind, that the reason you look over your shoulder (and a second time is not bad) is to check whether the lane is open. Small vehicles, such as motorcycles, move in and out of blind spots quickly. An object might fall off of a truck.
Observe the diagram where the various blind spots occur. These are also called “no zones.”