North Carolina DWI law is primarily governed by North Carolina General Statute Sect. 20-138.1 and Sect. 20-16. Like many states, North Carolina DWI law includes both a traditional driving while impaired charge, and a per se charge. Typically, when someone is arrested for DWI or a related North Carolina drunk driving charge, they will confront both charges.
North Carolina DWI law, for purposes of the traditional driving while impaired charge, relates to "appreciable impairment" while driving. This count does not depend on a particular blood alcohol level, such as North Carolina’s per se law, which relates to a blood or breath alcohol level of .08% or higher. The prosecutor will attempt to prove the traditional North Carolina DWI charge by demonstrating appreciable impairment through the suspect’s driving pattern, their physical appearance, their performance on field sobriety tests, and the chemical test results.
North Carolina DWI law for the "per se" charge doesn’t care about how the individual was driving, how they appeared, how well or poorly they did on field sobriety tests, or anything else other than the chemical test results. For purposes of the North Carolina per se laws, the primary issue relates to blood or breath alcohol levels of .08% or higher. Current North Carolina law forbids the use of the roadside breath test for other than probable cause to arrest someone for drunk driving; this means that the roadside tests are not to be used to establish impairment or violation of the per se law. However, other states, such as California, are now allowing these roadside test results into evidence.
