According to HR Hero, it is usually not a federal legal requirement for employers to reimburse employees for mileage; however, Palay Law does note that California has a state law requiring reimbursement. Many employers do choose to reimburse some expenses for the work use of a vehicle. The reimbursement amount typically depends on the standard business mileage rate set by the Internal Revenue Service each year, and businesses may also offer additional reimbursement for costs like parking or tolls.
According to TurboTax, employees can claim their work travel expenses on their income tax returns as a deduction whether the employer reimburses mileage or not. However, the amount that can be claimed depends on factors such as the employer's mileage reimbursement policies and the person's income, so it's important to seek a tax professional for advice.