Unlawful police stops and unlawful arrests are both common reasons for getting DUI
charges dismissed. Law enforcement must have probable cause in order to pull you
over. Stopping and searching a vehicle or a person requires probable cause or else
it is a violation of the Fourth Amendment, "unlawful search and seizure."
Even if the officer had probable cause to pull you over, the evidence from the field
sobriety tests may not have been enough to warrant an arrest. These tests are up
to the interpretation of the administering officer, making them subjective. They
can also be administered improperly. If either happened in your case, you absolutely
have the right to seek attorney counsel in hopes of proving unlawful arrest or an
unlawful stop.