If you're an employee -- someone who receives a Form W-2 for their services -- you can no longer claim such a deduction.  Unfortunately, job-related expenses for employees are no longer deductible under the new law.  Please see the TurboTax FAQ "Can employees deduct any job-related expenses?" below for more information. 

https://ttlc.intuit.com/replies/3300622

However, if you're self-employed, please see the TurboTax FAQ "Where do I enter my self-employment business expenses, like home office, vehicle mileage, and supplies?" below for guidance.  If you use your navigation system for personal and business use, you would need to allocate the fees based on the percentage of business use and only claim the business use portion of the fees.

https://ttlc.intuit.com/replies/5802554