Final answer:
While specific percentages of car-related deaths involving drugs are not provided, historical data shows a shift where drug overdose deaths surpassed vehicular accident deaths. The CDC and similar agencies report on drug use and driving, and it would be necessary to review their latest data for a precise percentage.
Step-by-step explanation:
Assessing the percentage of car-related deaths involving drugs in America is complex and requires careful analysis of traffic safety and public health data. From historical trends, we know that in 1999, motor vehicle crashes resulted in more than twice as many accidental deaths compared to drug overdoses. However, by 2014, accidental deaths from drug overdoses had surpassed those from car crashes by nearly 40%, with the majority of these overdoses attributed to heroin and opioid painkillers. It's important to differentiate between drug overdose deaths and car-related deaths caused by drug-impaired driving. The question seems to pertain more to the latter. Although specific percentages of drug-involved car-related deaths are not provided in the referenced statistics, the Centers for Disease Control and Prevention (CDC) and other agencies provide reports that can be used to make an estimation.
For instance, the information regarding driver error as a leading cause of fatal auto accidents can be used to extrapolate data regarding incidents where drugs may have played a part. With the increasing rates of opioid painkiller and heroin use, detailed analysis, including figures like the correlation of drug overdose rates with prescription rates (as seen with West Virginia's OxyContin issue), can be significant in estimating the impact of drugs on driving fatalities. To provide a precise percentage, a thorough review of the latest data from sources like the CDC or U.S. Census Bureau would be requisite, considering the ever-changing landscape of substance abuse and driving behaviors.