Final answer:
In the past 30 years, the number of years of potential life lost due to alcohol-related highway fatalities has decreased, supported by advancements in legislation, vehicle safety, enforcement, and public health awareness (option b).
Step-by-step explanation:
Regarding the number of years of potential life lost (YPLL) as a result of alcohol-related highway fatalities over the past 30 years, the answer is b. has decreased. Evidence suggests that there have been notable changes in legislation, such as the National Minimum Alcohal consumption Age Act of 1984, improvements in vehicle safety, increased enforcement of alcohal consumption and driving laws, and public health campaigns that have collectively contributed to a reduction in alcohol-related highway fatalities. Although data might show fluctuations from year to year, a general downward trend in these fatalities can be correlated with an overall increase in global life expectancy, indicating progress in road safety and health care.
Hence, the answer is option b.