Final answer:
Reinstating a federal law requiring motorcyclists to wear helmets would likely lead to a decrease in deaths, as helmets are known to reduce head injuries. Research supports the effectiveness of protective gear in preventing serious injuries.
Step-by-step explanation:
The most likely result of reinstating a federal law requiring motorcyclists to wear helmets would be Option 3: More people would wear helmets, so deaths would decrease. This expectation is based on the understanding that helmets are a form of protective gear that substantially reduce the risk of head injuries during accidents. Similar safety measures in other contexts, such as the requirement to wear seat belts in automobiles, have been shown to reduce the number of serious injuries and fatalities. Therefore, a helmet law for motorcyclists would likely lead to a similar outcome in terms of increased safety and reduced fatalities.
Research, such as the study by Buckley et al. and Cocello et al., has indicated that appropriate safety gear, including higher-rated helmets, can help prevent serious injuries like concussions and head trauma. This reinforces the idea that mandatory helmet laws would contribute to enhancing road safety for motorcyclists.