In California, almost everyone arrested for DUI / Drunk Driving does some form of field sobriety tests. Some of the most common tests are walk the line, finger to nose, stand on one foot and estimate 30 seconds. Many different police agencies either use a variation of these test or have their own such as count backwards from 100 or say the alphabet without singing. All of the tests are completely voluntary. The tests are also designed to make it difficult to do them with 100% accuracy. Being investigated for DUI / Drunk Driving is a very scary and intimidating experience. In addition, not everyone has the same physical ability to perform these tests. Performance and administration of field sobriety tests are a main focus of attacking the prosecution case in defending DUI / Drunk Driving cases.