California taxes are based on the information on your W-2 and your federal return. Your 401K contributions are normally reported in Box 12 of your W-2, with code D, and are pre-tax. The employee 401K contribution limit for 2019 is $19,000, which includes all elective employee salary referrals. Most plans do not permit employee contributions outside of payroll.
Employers can offer a pre-tax commuter parking benefit. See this IRS reference: https://www.irs.gov/government-entities/federal-state-local-governments/qualified-parking-fringe-ben...
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
