Driving under the influence sounds like a better idea while high on marijuana

Respondents who were high at the time of survey were also more likely to agree that "It is OK to drive a little bit stoned," that they might drive high "In certain situations" and that they would not get caught driving while high.

"When people are sober, most acknowledge they can't safely drive under the influence of alcohol or marijuana. The problem is, being intoxicated affects our perceptions of risk," said Jane Allen, research analyst at RTI and co-author of the study. "The public health community would do well to address this in campaign planning and development."

This study, published in Health Education Research, suggests that campaigns may benefit from understanding how messaging functions within the context of intoxication. A useful area for future research would be to assess whether some messages -- including both content and message characteristics -- are more memorable or more persuasive than others among those who are high. This study also strongly suggests that online public health surveys should routinely measure the proportion of the sample that completed the survey while under the influence of marijuana, alcohol or other intoxicants.

The data comes from surveys of 1,352 marijuana users in Colorado and Washington in 2014, and the data was refined to include 865 respondents reporting marijuana or hashish use in the past 30 days. More than 16 percent of participants reported being high at the time of survey administration.

Over the past decade, nearly half of U.S. states have legalized marijuana for medical or recreational purposes, and at least 10 states are currently considering recreational marijuana ballot initiatives.