I work in transportation and have unreimbursed travel expenses and need to k ow what the standard deduction for this is

You have a choice of Itemized Deductions or the Standard Deduction. There can be no Standard Deduction for travel expenses.

Employee business expenses are part of Itemized Deductions. They have been repealed for Federal purposes as of 2018. They may still be available for your state.

If you are referring to Per Diem, please see this LINK. Per Diem travel expenses are still permitted on Schedule C.