What is meant by "selective perception" when talking about driving?

You are always aware of your surroundings because the brain is constantly working to analyse and process all the impressions that your senses produce. This is called perception.

In order for you to be able to pay attention to the right things, rather than all things, the brain selects the most important impressions. This is called selective perception.

When you are starting out as a driver your brain has not yet learned which impressions are the most important. This means that you sometimes might pay attention to the wrong things, make wrong assessments or make incorrect decisions.