How long after passing the C1 test can you take the B1 test?

[LenaLee]

B1 driver's license can only be obtained through upgrading. The conditions for upgrading to B1 are: holding a C1, C2, C3, or C4 license for more than three years with no full-score record in the previous two cycles; or holding an A3 or B2 license for more than one year with no full-score record in the previous cycle and no record of being primarily responsible for a fatal accident. Below is additional information: 1. B1 driver's license: The vehicle types permitted for B1 license: medium-sized buses. Permitted vehicles: medium-sized passenger vehicles (including urban buses with a capacity of 10 to 19 people). Other permitted vehicle types: C1, C2, C3, C4, M. 2. Upgrade conditions: You must have held a (C1) license for more than three years, be between 21-50 years old, and have no full-score (12 points) record in the current scoring cycle (this year) and the most recent scoring cycle (last year) before applying. You can then apply for the upgrade at the local vehicle management office in your registered residence.