D was charged in a two-count criminal complaint with two misdemeanor violations of the California Vehicle Code. Count 1 charged that D passed another vehicle without maintaining the 'safe distance' required by. The second count charged that D had been involved in an accident but had failed to stop and identify himself as required by 20002 (a) (1) (Supp. 1971). D demurred to Count 2 on the ground that it violated his privilege against compulsory self-incrimination. His position was ultimately sustained by the California Supreme Court. That court held that the privilege protected a driver who 'reasonably believes that compliance with the statute will result in self-incrimination.' Here the court found that Byers' apprehensions were reasonable because compliance with 20002 (a) (1) confronted him with 'substantial hazards of self-incrimination.' Nevertheless, the court upheld the validity of the statute by inserting a judicially created use restriction on the disclosures that it required. The court concluded, however, that it would be 'unfair' to punish Byers for his failure to comply with the statute because he could not reasonably have anticipated the judicial promulgation of the use restriction. The Supreme Court granted certiorari to assess the validity of the California Supreme Court's premise that without a use restriction 20002 (a) (1) would violate the privilege against compulsory self-incrimination.