In the 1980s, the National Highway Traffic Safety Administration developed standardized field sobriety tests. They help police officers determine whether motorists are operating their vehicles while under the influence of alcohol, and they are commonly used in parts of the country where implied consent laws only allow chemical tests to be ordered after drunk driving arrests have been made. In Minnesota, field sobriety tests are less common. This is because the implied consent law allows police officers to demand breath tests when they suspect motorists may be intoxicated but have not yet made an arrest.
The walk-and-turn test
The walk-and-turn test is often the part of the standardized field sobriety test that motorist find most challenging. The walk-and-turn test has two stages. During the instruction stage, motorists must stand heel-to-toe with their arms by their side as they listed to directions. During the performance stage, motorists walk up and down an imaginary or real line while taking heel-to-toe steps. Motorists are told to pivot and return to the starting point after taking nine steps. While motorists take the walk-and-turn test, police officers look for signs of intoxication like falling, stumbling or failing to follow directions.
An unreliable test
The NHTSA concedes that the walk-and-turn test has an accuracy rate of just 66%, and that modest figure is only achieved when police officers follow the guidelines. Foot injuries or medical conditions that affect balance can make the test difficult or impossible to complete, and motorists over the age of 65 or more than 50 pounds overweight could find it extremely challenging even if they are in good health. The results of a field sobriety test are not reliable enough to provide proof of intoxication, so police officers usually conduct chemical tests when they make DUI arrests.
A law enforcement tool
The standardized field sobriety test is a law enforcement tool that was developed by NHTSA. The walk-and-turn test is designed to help police officers identify the signs of intoxication, but it is only reliable about 66% of the time. Field sobriety tests are conducted less frequently in states like Minnesota that allow police officers to order breath tests before they make drunk driving arrests.