Protecting The Rights And Freedom Of The Accused

Police car at night
  1. Home
  2.  » 
  3. DWI
  4.  » What is a ‘per se’ DWI and how can it impact a person?

What is a ‘per se’ DWI and how can it impact a person?

On Behalf of | May 21, 2024 | DWI |

Driving while impaired or intoxicated, commonly known as DWI, is a serious offense. Throughout the country, per se DWI laws in particular often trouble people for several reasons.

This means learning about what exactly per se DWIs are is important.


The term “per se” is Latin for “by itself” or “in itself.” In the context of DWI laws, per se DWI refers to the illegal act of operating a vehicle with a blood alcohol concentration, or BAC, at or above a certain level, regardless of whether the driver shows outward signs of impairment.

The legal BAC limit in Missouri is currently at 0.08 percent for drivers aged 21 and older. When a driver’s BAC meets or exceeds this percentage, it constitutes a per se violation of DWI laws.


BAC levels are important in DWI cases because they provide an objective measure of intoxication. Unlike other forms of DWI that rely on observations of a driver’s behavior, such as stumbling around or slurring words, per se DWI charges depend solely on the BAC measurement. Law enforcement officers typically use breath tests, blood tests or urine tests to determine a driver’s BAC.


Drivers charged with per se DWI face serious penalties, including fines, license suspension, mandatory alcohol education programs and even jail time in some cases. The severity of these penalties often depends on the driver’s prior DWI history and the specific circumstances of the arrest.

Understanding these laws helps drivers make decisions and avoid further trouble. Those facing DWI charges can also avoid anxiety during this time by staying informed.