MOTOR VEHICLES ‑- DRIVER EDUCATION ACT ‑- PENALTY ASSESSMENT ‑- NONPAYMENT ‑- CONFINEMENT The penalty assessment imposed by § 4, chapter 39, Laws of 1963 (RCW 46.81.030) upon persons convicted of certain offenses involving the use of motor vehicles or the licensing of vehicle operators is in the nature of a fine, not a tax; therefore, such persons may be confined for nonpayment of the fine.