As someone who has navigated rental car issues on more TDYs than I can count, I can tell you that a rental car can make your TDY way more productive – or it can turn into a bureaucratic nightmare if you don’t handle it right. I learned everything the hard way. Let me show you how to navigate the Defense Travel System rental requirements while actually getting the vehicle you need.
Authorized Rental Car Use
Probably should have led with this: rental cars need to be authorized in your travel orders before you can get reimbursed. If your mission justifies a rental, make absolutely sure it’s in the orders before you leave. Trying to add rental authorization after the fact will complicate your voucher processing big time.
That’s what makes getting this right upfront endearing to us veteran travelers: government rates through contracted vendors usually require booking through DTS or your designated travel agency. Has gotten complicated with all the different vendor programs, but know your organization’s specific requirements so you don’t get caught off guard.
Vehicle Category Selection
Compact cars are the standard authorization for solo travelers. Want something bigger? You’ll need justification – multiple travelers, hauling equipment, or rough road conditions all work. Document why you need a larger vehicle to protect yourself if auditors come asking questions later.

Counter upgrades live in a bit of a gray area. If they offer you a free upgrade, most travelers accept without any issues. Paid upgrades from your own pocket? That’s your business. Just don’t charge the government for unauthorized upgrades – that creates real problems.
Insurance Considerations
Government travel generally includes insurance coverage through the rental agreement or government programs. That means you typically don’t need additional insurance at the counter, and it won’t be reimbursable anyway. Just be aware that personal use during TDY might fall outside government coverage.
Take the time to understand exactly what coverage applies to your situation. It prevents both unnecessary expenses and potential gaps. Your organization’s travel office can clarify the specifics.
Fuel and Mileage
Always return vehicles with full tanks – rental company fuel charges are ridiculously inflated. Plan your final fill-up near the return location to save money. Keep those fuel receipts to document your expenses for reimbursement.
Mileage between your lodging and work sites is typically covered in the rental. Personal use mileage might need separate accounting depending on your organization’s policies. Just remember – excessive personal use on government rentals will definitely invite scrutiny.
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