In addition to the standardized field sobriety tests, police officers routinely conduct what are referred to as "non-standardized tests." Although we have seen many different unique tests, the most common is the alphabet and count backwards tests.
Unlike field sobriety tests which are based in science, the alphabet and count backwards tests are tests that have been developed independently by police officers, not scientists. Because there are no standard rules for these tests, the officers' interpretation of whether you passed or failed is always skewed in favor of the police.
The key thing that any decent owi trial lawyer should know is how to attack these tests. The best way to do this is to go after the cop about the test itself and how there is no set of rules behind its administration. We have won many drunk driving jury trials doing just that.