I work for a NJ School District, while on the job they sent me to various schools using my own vehicle. I was on light duty from getting injured on the job, before the uncompensated mileage issue occurred. My supervisor ordered me to go to various schools in the school district using my own vehicle for 5 months. I was then told by a coordinator to put in a voucher for the mileage
but the administration refused to pay for the mileage. The contract I'm under doesn't mention that they pay mileage to workers in my position but they do pay administators, managers, teachers and drivers. The position I was in during my tenure on light duty by their own description (administration) was as a "floater" (a worker who fills in as needed). That position as the norm has the use of a district vehicle but I wasn't offered or given one, with the exception of when I filled in as the district courier. My normal position is as a custodian in one assigned school that doesn't require any or practically any travel. My question is; is the administration liable to pay my mileage?

No. Unless you have a contract that says otherwise, your employer is not obligated to pay mileage.

You may, however, be able to deduct it when you file your taxes.

Doesn't that mean my employer has to sign a statement, stating that my vehicle was used for work purposes?

The only state where an employer is required by law to reimburse an employee for mileage is California, and even there I believe there are exceptions and/or limitations on the employer's liability. Your poll may reflect people's opinions, but it is not going to change the law. The law does not require your employer to pay for mileage, no matter how many people tell you they think you should. It doesn't matter whether your employer signs a statement or not.

On rereading your post, it occured to me that you might be asking how to go about taking the mileage as a tax deduction. That is outside my range of experience; you will have to ask your tax advisor.

Yes, I was asking from your first reply if the IRS required written confirmation from my employer that the vehicle was used in the course of work.

Couldn't tell you. Check with whoever helps you do your taxes.

No, the IRS does not. Just like it doesn't require you to file documentation for most of your other itemized deductions. However, if you have your own records, you may need them if you are audited or the deduction is otherwise questioned by the IRS.