Using opioids appears to double the risk that a driver will trigger a fatal crash, regardless of whether alcohol is in the mix, a new study by Columbia University researchers found.

The study found that more than half of the crashes occurred because the narcotics user had failed to keep the vehicle in its lane. Dr. Guohua Li said the findings demonstrate the ripple effect of the opioid crisis. “The impact … goes far beyond the body count from overdoses,” Li said. He said it should serve as a warning to clinicians and patients about the risks of driving when using prescription narcotics.

Here’s a look at an analysis of data from 18,000 fatal two-car crashes from Jan. 1 1993 to Dec. 31, 2016.

7 percent

Fatally injured drivers in past two decades with prescription narcotics in their system, up from 1 percent.

32 percent

Hydrocodone, the active ingredient of Vicodin, detected among drivers at fault who tested positive for opioids. Nearly 27 percent used morphine; more than 18 percent used oxycodone, marketed as OxyContin.

55 percent

Opioid user did not stay in lane; it was group’s most common error.