Testing blood alcohol concentration (BAC) based on breath samples has been a staple of roadside law enforcement since the late 1930s, when Prof. Rolla H. Harger of Indiana University developed a device called the “drunkometer.” Drivers who fail the tests face prosecutions for violating laws that prohibit driving with a certain BAC, which are referred to as “per se” statutes. Per se DWI statutes do not require proof that the motorist’s ability to drive was affected by alcohol: simply ... Read More »