California Code, Penal Code - PEN § 853.5

(a) Except as otherwise provided by law, in any case in which a person is arrested for an offense declared to be an infraction, the person may be released according to the procedures set forth by this chapter for the release of persons arrested for an offense declared to be a misdemeanor. In all cases, except as specified in Sections 40302, 40303, 40305, and 40305.5 of the Vehicle Code, in which a person is arrested for an infraction, a peace officer shall only require the arrestee to present his or her driver's license or other satisfactory evidence of his or her identity for examination and to sign a written promise to appear contained in a notice to appear. If the arrestee does not have a driver's license or other satisfactory evidence of identity in his or her possession, the officer may require the arrestee to place a right thumbprint, or a left thumbprint or fingerprint if the person has a missing or disfigured right thumb, on the notice to appear.Except for law enforcement purposes relating to the identity of the arrestee, no person or entity may sell, give away, allow the distribution of, include in a database, or create a database with, this print. Only if the arrestee refuses to sign a written promise, has no satisfactory identification, or refuses to provide a thumbprint or fingerprint may the arrestee be taken into custody.

(b) A person contesting a charge by claiming under penalty of perjury not to be the person issued the notice to appear may choose to submit a right thumbprint, or a left thumbprint if the person has a missing or disfigured right thumb, to the issuing court through his or her local law enforcement agency for comparison with the one placed on the notice to appear. A local law enforcement agency providing this service may charge the requester no more than the actual costs. The issuing court may refer the thumbprint submitted and the notice to appear to the prosecuting attorney for comparison of the thumbprints. When there is no thumbprint or fingerprint on the notice to appear, or when the comparison of thumbprints is inconclusive, the court shall refer the notice to appear or copy thereof back to the issuing agency for further investigation, unless the court finds that referral is not in the interest of justice.

(c) Upon initiation of the investigation or comparison process by referral of the court, the court shall continue the case and the speedy trial period shall be tolled for 45 days.

(d) Upon receipt of the issuing agency's or prosecuting attorney's response, the court may make a finding of factual innocence pursuant to Section 530.6 if the court determines that there is insufficient evidence that the person cited is the person charged and shall immediately notify the Department of Motor Vehicles of its determination. If the Department of Motor Vehicles determines the citation or citations in question formed the basis of a suspension or revocation of the person's driving privilege, the department shall immediately set aside the action.

(e) If the prosecuting attorney or issuing agency fails to respond to a court referral within 45 days, the court shall make a finding of factual innocence pursuant to Section 530.6, unless the court finds that a finding of factual innocence is not in the interest of justice.