It is crucial that motorists understand that bike lanes are real lanes on the road. They need to treat them the same way that they treat any other lane.
For instance, imagine that you're driving on a two-lane highway. Both lanes go the same way. You are in the left lane, but you want to turn right. Clearly, you don't turn right from the left lane. You check to make sure that the path is clear, merge into the right lane and then execute your turn at the proper time.
This is exactly what a driver should do when there is a bike lane on the right. Merging over blocks the lane so that cyclists stay behind the car.
Unfortunately, many drivers ignore the bike lane or act like it doesn't exist. They just turn from their lane, right through the bike lane.
There are a lot of problems here. One is that there may already be a bike on the right side of the car that the driver doesn't see. The car could hit the bike while it's legally in the lane.
Another issue is that a cyclist may have no idea that the driver plans to turn right since the car has not merged into the bike lane. As the car turns, the cyclist could ride through on the bike lane and strike the side of the car.
It's clear that cyclists face a lot of dangers, especially when drivers do not understand the rules of the road. Make sure that you are well aware of your legal rights if you get involved in an accident.