From the drug czar's blog:

According to a recent national survey, 11 percent of weekend nighttime drivers tested positive for illicit drugs - five times as many as were under the influence of alcohol.

It's just perfect nonsense of the exact variety the drug czar's office specializes in. Testing positive for drugs just means the person has drugs in their system (which could have been ingested days or even weeks before getting behind the wheel). By contrast, those who were "under the influence of alcohol" were over the legal limit at the time they were driving. The drug czar is literally comparing people who may have smoked marijuana last week to people who are drunk right now. It's insane.

And, as is often the case when drug warriors wildly misinterpret scientific data, the report itself specifically warns against drawing exactly the types of conclusions claimed by the drug czar:

The reader is cautioned that drug presence does not necessarily imply impairment. For many drug types, drug presence can be detected long after any impairment that might affect driving has passed. For example, traces of marijuana can be detected in blood samples several weeks after chronic users stop ingestion. Also, whereas the impairment effects for various concentration levels of alcohol is well understood, little evidence is available to link concentrations of other drug types to driver performance.

Is that confusing to anyone? It really shouldn’t be. But, unfortunately for us all, it is the drug czar's job not to understand or acknowledge basic facts like these. Once one comes to understand that our drug policies are routinely based on complete nonsense, it ceases to be a mystery why we achieve such dismal results.