Final answer:
To safely turn or change lanes, a driver must use turn signals, check mirrors, and look over their shoulder to ensure the blind spot is clear.
Step-by-step explanation:
When you want to turn or change lanes, you should use your turn signals and check your mirrors as well as look over your shoulder. It is critical to use your turn signals to communicate your intention to other drivers and to check your mirrors to see the traffic situation around you. Additionally, looking over your shoulder is necessary to check the blind spot, an area that mirrors may not cover. In contrast, actions such as using your horn and speeding up, texting your friends, and updating social media are not safe driving practices and are unrelated to the safe procedure of turning or changing lanes.