California Code, Vehicle Code - VEH § 23624

Only one challenge shall be permitted to the constitutionality of a separate conviction of a violation of Section 14601, 14601.2, 23152, or 23153, which was entered in a separate proceeding. When a proceeding to declare a separate judgment of conviction constitutionally invalid has been held, a determination by the court that the separate conviction is constitutional precludes any subsequent attack on constitutional grounds in a subsequent prosecution in which the same separate conviction is charged. In addition, any determination that a separate conviction is unconstitutional precludes any allegation or use of that separate conviction in any judicial or administrative proceeding, and the department shall strike that separate conviction from its records. Pursuant to Section 1803, the court shall report to the Department of Motor Vehicles any determination upholding a conviction on constitutional grounds and any determination that a conviction is unconstitutional.

This section shall not preclude a subsequent challenge to a conviction if, at a later time, a subsequent statute or appellate court decision having retroactive application affords any new basis to challenge the constitutionality of the conviction.