Four-of-5 U.S. adults don't allow smoking in homes Eighty-percent of U.S. adults say they don't allow smoking in their homes, while 75 percent say they don't allow smoking in their vehicles, health officials say. ATLANTA, May 16 (UPI) -- Four-of-5 U.S. adults say they don't allow smoking in their homes, while 75 percent say they don't allow smoking in their vehicles, health officials say. Dr. Tim McAfee, director of the Office on Smoking and Health at Centers for Disease Control and Prevention, said the National Adult Tobacco Survey respondents were classified as having smoke-free rules if they never allow smoking inside their homes or vehicles. The study, published in the journal Preventing Chronic Disease, found almost 11 million non-smoking adults continue to be exposed to secondhand smoke in their home, and almost 17 million non-smoking adults continue to be exposed to secondhand smoke in a vehicle. The study's state-by-state data showed the highest prevalence of smoke-free rules in homes and vehicles occurred in many states with comprehensive smoke-free laws and longstanding tobacco control programs. "We have made tremendous progress in the last 15 years protecting people in public spaces from secondhand smoke," McAfee said in a statement. The good news is that people are applying the same protection in their homes and vehicles. However, millions of non-smokers, many of whom are children, remain exposed to secondhand smoke in these environments. Eighty-nine percent of non-smokers report having smoke-free home rules, but 48 percent of smokers have them. Eighty-five percent of non-smokers report having smoke-free vehicle rules, but only 27 percent of smokers do, the study said.