You may have seen fictional police officers in movies or TV shows ask drivers to walk in a straight line. You may even have had real officers ask you to do the same.
Understanding more about why they do so can help you if you face driving while intoxicated (DWI) charges as a result of taking these tests.
They are trying to show you are unfit to drive
The aim of the police in asking you to walk in a straight line is to determine whether or not you are drunk. The fact they asked you to do the test suggests they probably think you are too drunk to be driving.
Walking in a straight line, then turning and coming back, is one of three so-called field sobriety tests by the National Highway Traffic and Safety Administration (NHTSA). The idea is that when taken together, the results have a high probability of determining whether or not a person is drunk. Police officers might ask a driver to take other tests of their own making, but it’s only the three that are officially recognized.
The other two are:
Standing on one leg: This tests your balance. The idea is that someone drunk will be unable to do this because alcohol affects balance. However, many other things, such as inner ear problems, a disability or nerves, could also cause someone to fail the tests.
Staring at a moving item: An officer will put their finger or a pen up in front of your eyes and then move it about. You need to keep starting straight at it as it moves. If they determine your eyes are not following well, they’ll assume it is because you are drunk. Once again, there are plenty of reasons why someone might fail the test even when completely sober.
If you fail any or all of the tests, the officer will likely arrest you and charge you with DWI. Getting legal help to explain why you failed will increase the chance you beat the charge and avoid the consequences a conviction will bring.