If stopped by a police officer after having consumed alcohol or drugs, remember that the field sobriety tests are optional. You do NOT have to try to perform any acrobatics, gymnastics or roadside tests, San Diego California DUI lawyers remind.
California DUI cops may request a person to do roadside tests if suspected of driving under the influence of drugs or marijuana. You do NOT have to do them. You only must do a blood or breath test if arrested for DUI, San Diego DUI attorneys point out in various articles.
Here's a sample video of field testing by Colorado DUI cop looking for marijuana impairment, entitled "Feds test how stoned is too stoned to drive." How one does on these tests has little or nothing to do with driving a motor vehicle.
Remember to remain totally silent from the beginning of your encounter. All you have to do is provide license, registration and insurance if stopped. Politely and persistently be quiet.