Marijuana has now been legalized in numerous states. Some people believe this has resulted in an increase of impaired drivers on the road and that traffic fatalities have increased as a result. While some drug tests taken at the scene of accidents do indicate the presence of marijuana, such tests only reveal that the drug has been used—they do not indicate actual intoxication, as indicators of marijuana use can stay in the system for days or even weeks after actual use.
What are some likely ethical issues arising from such testing? How do you think a status of “impaired” can be legally established to enforce safety if exact intoxication is not measured by current tests?