The main idea is knowing when a booster is no longer needed by checking the belt fit. Use a booster until the seat belt fits properly on the child without the booster. A proper fit means the lap belt lies low and snug across the hips and thighs, not the stomach, and the shoulder belt crosses the chest and shoulder, not the neck or face. When the belt sits correctly like this, the child is protected by the vehicle’s belt alone. Keeping a booster after the belt fits can lead to poor belt placement and reduced protection. Boosters are for older kids who still need help getting the belt to fit right, not for infants. Other statements suggesting boosters are optional after a certain age, or that the seat belt should never be used with a booster, don’t reflect how the belt should position and protect the body.

Blacking out is the term used for memory loss caused by alcohol. It happens when alcohol impairs the brain’s ability to form new memories, so experiences that occur while intoxicated aren’t encoded into long-term memory. The person may appear to be functioning normally, but later cannot recall those events. This occurs because high blood alcohol content disrupts the hippocampus, which is central to memory formation. Other phrases like blanking out or blinding out aren’t standard terms for this phenomenon, and “forget memory” isn’t a typical label used in health education. There are variations, such as complete versus fragmentary blackouts, but the core idea is that memory encoding is impaired during intoxication.

Hazard lights are used to alert other drivers that your vehicle is a stationary hazard and to make you more visible. When a car is disabled or pulled over, these lights flash to warn approaching traffic to slow down and pass with caution, reducing the chance of a crash. They help drivers see you from a distance or in low-visibility conditions, not just pedestrians. They don’t indicate an intent to move immediately—that’s what turn signals are for—nor are they a signal that you’re about to turn. Use them whenever you’re stopped in a way that could create danger for others, such as on the side of the road or in traffic, to communicate the hazard to every road user.

Head injuries are the most common type of injury shown in the bike crash data, making up about three-quarters of the cases. That 75% stands out as the largest share among the options, so it best matches what the data report for head injuries. The other percentages—60%, 50%, and 25%—are smaller shares and don’t align with the data’s balance of injury types. This helps explain why helmets are so important: head injuries dominate the risk in crashes, and protective gear can significantly reduce both occurrence and severity.