What are the two primary methods police use to detect and measure drugs in an impaired driver?

The correct answer highlights the dual approach taken by law enforcement to effectively identify and measure drug impairment in drivers. When assessing a potentially impaired driver, police often rely on evaluations conducted by a Drug Recognition Expert (DRE), who is specially trained to recognize the signs and symptoms of drug influence. This expert utilizes a detailed systematic approach that includes a series of evaluations, observations, and tests focusing on physical and behavioral indicators.

In conjunction with the evaluation by a DRE, law enforcement typically employs a blood test to quantify the specific substances present in the driver's system. Blood tests provide legal and medical evidence of drug levels, allowing for the accurate determination of impairment. This combination of a behavioral assessment and quantitative testing is essential in accurately establishing that a driver is impaired due to drug consumption.

Other options mention various tests that may be relevant but do not capture the comprehensive pairing of expert evaluation and scientifically validated measurement, which is paramount in addressing drug impairment on the road.