Question:

Do I have a choice of chemical tests? Which should I choose?

Answer:

In California, you are supposed to be given a choice of blood or breath testing. Urine testing can be required if neither blood nor breath is available, or if the officer reasonably suspects the presence of drugs. If a breath test is chosen, the officer is supposed to advise you that, because a breath sample will not be saved for later reanalysis by the defense, you are entitled to a second test of blood; many officers, however, fail to provide this information.

Analysis of a blood sample is potentially the most accurate. Breath machines are susceptible to a number of problems rendering them often unreliable. The least accurate is urinalysis.