The role of screening road users for psychoactive substances acts as a deterrent and provides a scientific basis to prosecute offenders as well as legislate against impaired driving. This study utilized a portable electronic digital screening device called oral screen to establish the prevalence of substances of abuse among road users in selected cities in Nigeria. The study also utilized a virtual driving simulator to investigate skills impairment under various conditions. Biological fluids such as blood, saliva, and urine were screened. Skills impairment characterized by unsafe driving...