These tests are very subjective and if not administered correctly do not assist. These tests are completely voluntary. The officer cannot threaten you with arrest if you refuse to take them. Because some physical disabilities affect the reliability of the tests, officers are trained to ask about such disabilities. If the officer did not do so, the results are invalid.
Independent witnesses are an excellent source of information and support.
If you have not already done so, record the names of any such witnesses. The length of time the officer used to investigate at roadside is very relevant. Try to recall how long you were at roadside and the length of time before a chemical test was taken. A chemical test is a blood, breath or urine test. The length of time between the investigation and time of chemical test can seriously affect the state s case.