Final answer:
Turning your head to check your blind spot before changing lanes or merging is known as the shoulder check, and it's a critical component of safe driving practices.
Step-by-step explanation:
The act of turning your head and checking your blind spot before changing lanes, driving away from a curb, or merging your vehicle into traffic is known as the shoulder check. This is a vital defensive driving technique to ensure that the area beside and slightly behind the driver's side, which is not visible in the rear-view mirrors, is clear of other vehicles, cyclists, or pedestrians. It's essential for safe driving to perform a shoulder check to prevent collisions and ensure the smooth flow of traffic.