Petitioner, a California motorist, was involved in an automobile collision on March 18, 1971. Both drivers filed accident reports with the California Department of Motor Vehicles as required by the California Financial Responsibility Laws. Without affording petitioner a hearing on the question of potential liability, and based solely on the contents of the accident reports, the Department found that there was a reasonable possibility that a judgment might be recovered against petitioner as a result of the accident. Since petitioner was uninsured and could not deposit security, his license was suspended. The Supreme Court of California reversed, holding that prior to suspension “a hearing is required and that at such a hearing the licensee is entitled to review the reports or other evidence upon which the department contemplates determining that he is possibly responsible for the accident, and to present reports or testimony to establish his claim of nonculpability, all within reasonable due process procedures which the department may employ.” Rios v. Cozens, 7 Cal. 3d 792, 799, 499 P. 2d 979, 984 (1972).
*426We are unable to determine, however, whether the California Supreme Court based its holding upon the Due Process Clause of the Fourteenth Amendment to the Constitution of the United States, or upon the equivalent provision of the California Constitution, or both. In reaching its result in this case, the California court relied primarily upon this Court’s decisions in Bell v. Burson, 402 U. S. 535 (1971), and Jennings v. Mahoney, 404 U. S. 25 (1971), but also cited its own decisions in Randone v. Appellate Department, 5 Cal. 3d 536, 488 P. 2d 13 (1971); Blair v. Pitchess, 5 Cal. 3d 258, 486 P. 2d 1242 (1971); McCallop v. Carberry, 1 Cal. 3d 903, 464 P.2d 122 (1970), and Cline v. Credit Bureau of Santa Clara Valley, 1 Cal. 3d 908, 464 P. 2d 125 (1970), which apparently were premised upon both the state and federal provisions. In addition, the court in Rios specifically overruled its own prior decisions in Orr v. Superior Court, 71 Cal. 2d 220, 454 P. 2d 712 (1969), and Escobedo v. State of California, 35 Cal. 2d 870, 222 P. 2d 1 (1950), which had upheld the procedures here under attack under both the state and federal provisions. Thus, as in Mental Hygiene Dept. v. Kirchner, 380 U. S. 194, 196-197 (1965), “[w]hile we might speculate from the choice of words used in the opinion, and the authorities cited by the court, which provision was the basis for the judgment of the state court, we are unable to say with any degree of certainty that the judgment of the California Supreme Court was not based on an adequate and independent nonfederal ground.” We therefore grant the State of California’s petition for certio-rari, vacate the judgment of the Supreme Court of California, and remand the cause to that court for such further proceedings as may be appropriate. California v. Krivda, 409 U. S. 33 (1972); Mental Hygiene Dept. v. Kirchner, supra; Minnesota v. National Tea Co., 309 *427U. S. 551 (1940); State Tax Comm’n v. Van Cott, 306 U. S. 511 (1939).
It is so ordered.