Underage college students are more likely to drive after smoking pot or to ride in a car with a driver who had, according to a recent study Reuters reported.

Researchers from the University of Massachusetts at Amherst found that although college freshmen were less likely to smoke marijuana than drink alcohol, they were much more likely to drive after smoking pot.

"That's a pretty high number and this is something we should be talking about," Jennifer Whitehill, lead author of the study, and a public health researcher at the University of Massachusetts at Amherst, told Reuters. "In the public health arena, we feel like we've had some great success with reducing driving after drinking over the last few decades and so one of the motives for the study was trying to see if there is anything we could learn from alcohol that could apply here."

For the study, researchers collected data from an ongoing longitudinal study involving more than 300 incoming college freshmen at the University of Washington and University of Wisconsin, Madison.

Researchers found that overall 30 percent of male and 13 percent of female study participants said they used marijuana in the 28 days prior to being surveyed, while 67 percent of the men and 64 of the women reported using alcohol over the same period. Overall, 23 percent of the men reported using both marijuana and alcohol over the previous month compared to just 9 percent of the women.

"But our study quantifies the prevalence, which is useful in setting priorities for public health action. We also quantified the likelihood that someone will ride as a passenger with a driver who has used marijuana, and how much it rises with the proportion of their friends who use marijuana," Whitehill said.

The findings were recently published in JAMA Pediatrics.