You can deduct expenses that are ordinary and necessary for conducting your business. For example, if you rent an office and have to pay extra to rent a parking space in front for yourself or customers, that is a deductible business expense.
If the parking spot also has personal use, you may have to allocate it, depending on circumstances. For example, if you live in an apartment and have to pay extra for a second parking space for your personal vehicle that is also used in business, you have to allocate the expense by the percent of business use. But if the vehicle is your business-specific panel truck, with distinctive signage and carrying necessary equipment, then you can probably deduct the entire amount.
Generally, any employee benefit is part of their taxable income unless it meets a particular exception. There is an exception allowed for providing commuting assistance to your employees, this includes a parking space, a car pool service with at least 6 riders, or public transit. You can provide the employee with a parking space that costs up to $260 per month tax-free to the employee, it does not have to be included in their wages. However, it is NOT a deductible business expense to you.
If the parking space is more than $260 per month, then the excess is taxable to the employee and you must include it in their W-2 box 1, 3 and 5 wages and withhold employment taxes. Since it is treated as taxable wages to the employee, the expense is deductible to you as a wage expense.
See here pages 20-21 <a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/p15b.pdf">https://www.irs.gov/pub/irs-pdf/p15b.pdf</a>