Researchers Examine How Cannabis Use Affects Road Safety

As legal marijuana (cannabis) use grows, scientists are trying to better understand how it affects road safety, The New York Times reports.

According to the National Highway Traffic Safety Administration, studies have shown that cannabis can impair a driver’s ability to respond quickly to an obstacle and judge distance accurately.

Researchers are hoping to create breathalyzers that show how recently drivers used cannabis. They are also studying how cannabis impairs motor skills and reflexes for people who use cannabis regularly and for those who only use it occasionally.

Only a few states routinely test the blood of drivers who are involved in serious accidents for cannabis, the article notes. Police officers usually need a warrant to force a driver suspected of being impaired to provide a blood sample. Blood tests are an imprecise gauge of how impaired a person is, because they cannot reliably show how recently a person last used cannabis.

State laws on cannabis-impaired driving are confusing and inconsistent. This has made them difficult for police to enforce and for motorists to understand.