If i'm a food delivery driver (self-employed) who purchased a car last year. should i use one time depreciation if it shows my deductions are greater than my earnings?

[ThomasM125]

You can still benefit from the one time depreciation (section 179 or bonus depreciation) method even if you have a loss on your business. Any deduction not allowed in the current year can normally be applied to income in future years. 

One reason you may not want to take the special depreciation is that if you stop using the auto for business in future years, you may need to add back a portion of the special depreciation you deducted to  your taxable income in the year you stopped using the auto.

[meekwald]

You mentioned that "Any deduction not allowed in the current year can normally be applied to income in future years". Does that mean that they won't allow the full deduction? I ask this because in this case, they will be giving me money rather than me paying taxes. Thanks in advance

[ThomasM125]

The deduction will be allowed but it will only benefit you until it reduces your income to $0. For instance, if you had a business loss of $30,000 and other income of $10,000, you would use $10,000 of the loss in the current year to reduce your other income to $0. The rest of the loss would be considered a net operating loss that would be carried over to next year.