How to Fill Out and Upload the Constructed Travel Worksheet (CTW) in DTS

The Constructed Travel Worksheet is a cost-comparison form you complete when you want to travel by a mode other than the one the government would normally authorize, most often driving your own vehicle instead of flying. The worksheet calculates what the trip would have cost the government using commercial air, and that figure becomes the ceiling on what you can be reimbursed. You can download the current form and instructions from the Defense Travel Management Office at travel.dod.mil.¹

When You Need to File One

A worksheet is required whenever your one-way driving distance exceeds 400 miles, or 800 miles round trip. Trips at or below that threshold no longer require the form, a change reinstated by a JTR amendment effective January 31, 2025.² The same rule applies if you pick rail or bus travel when commercial air would have been the directed mode.

Local commands and agencies can impose stricter business rules that require a worksheet even on shorter trips, so ask your Defense Travel Administrator before assuming you’re clear. Unless your organization says otherwise, the worksheet is required for any en-route transportation mode other than commercial air or government-furnished transportation.¹

Data to Gather Before You Open the Form

Three numbers drive the whole worksheet: the government airfare for your route, the official driving distance, and the per diem rates for any places you’ll stop or stay. Sourcing matters. Travel clerks reject worksheets built on commercial booking quotes or personal GPS mileage.

GSA City Pair Airfare

The constructed cost of air travel comes from the GSA City Pair Program, which offers discounted contract fares for government travelers. Look up your route with the City Pair tool on the GSA site.³ Most routes list two fare types. The _CA fare is a deeply discounted capacity-controlled rate with limited seats, and the YCA fare guarantees last-seat availability at a higher price. Federal Travel Regulation 301-10.110 requires you to use the lower _CA fare when it’s available and meets mission needs.⁴ The gap between the two can be large, so booking early improves your chances of locking in the _CA rate.

Official Driving Distance

Mileage must come from the Defense Table of Official Distances at dtod.transport.mil. You need an active TEAMS account with DTOD access to log in and run distances. If you don’t have one, your Defense Travel Administrator or transportation office can pull the figure for you. Google Maps and other mapping tools are not accepted.

Per Diem Rates

If driving adds travel days, you’ll need per diem for your stopover locations and TDY destination. Use the GSA per diem tool at gsa.gov/travel/plan-a-trip/per-diem-rates and select the current fiscal year.⁵ Per diem for OCONUS locations and U.S. territories is set by the Department of Defense rather than GSA.

POV Mileage Rate

The 2026 reimbursement rate for a privately owned automobile on official travel is $0.725 per mile. If a government-furnished vehicle was available but you chose your own, the rate drops to $0.205 per mile.⁶

Working Through the Four Sections

The worksheet has four sections. Do them in order and the math stays clean.⁷

Section 1: Travel Itinerary

Enter each leg of the trip the government would have authorized, not the trip you’re actually taking. For each leg record the date, departure location, arrival location, transportation mode, and cost. For air travel include the fare class (YCA or _CA). For rail, note anything that affects cost, like a sleeper car for overnight travel. The cost of each leg is the ticket price plus taxes and fees. Leave out the travel management company transaction fee here; that goes in the next section.

Section 2: Constructed Cost

This section totals the government’s hypothetical cost and produces the number that caps your reimbursement.

Line 2A: transportation cost of your outbound leg.
Line 2B: transportation cost of your return leg.
Line 2C: total transportation cost for any other legs, such as connecting flights.
Line 2D: sum of 2A, 2B, and 2C. These are the only transportation expenses the JTR allows in the constructed cost.
Line 2E: the standard TMC transaction fee.
Line 2F: 2D plus 2E, your constructed cost.

Line 2F is the figure the Authorizing Official compares against your actual requested costs. Confirm you used the correct City Pair fare and included all applicable taxes before moving on.

Section 3: Potential Transportation Costs

Section 3 captures costs the government would have incurred if you had flown. Think of them as context for the AO rather than part of the constructed cost itself.

Line 3A: getting from home or duty station to the departure airport (taxi, rideshare, POV mileage).
Line 3B: local transportation at the TDY location.
Line 3C: costs tied to an authorized rental car at TDY, such as fuel, hotel parking, and tolls.
Line 3D: transportation from the arrival airport back to home or duty station on the return.
Line 3E: long-term parking at the departure airport during the TDY.
Line 3F: shipping for official materials or excess baggage fees.
Line 3G: constructed cost for additional official travelers riding in your POV. Multiply Line 2F by the number of passengers.

Line 3G is the one people most often miss. If colleagues are in the vehicle, their constructed airfare belongs in the comparison because the government would have bought each of them a ticket. That math often tips a POV request into full reimbursement territory.

Section 4: Additional Considerations

Check any boxes that explain why your chosen mode makes sense beyond pure cost. The form lists four: the authorized mode would have made you late for the mission; the authorized mode is unavailable or impractical; there is significant risk of delays from traffic, weather, or routing; or POV use is more efficient, economical, or faster for the mission. You are not required to check any, but a checked box with a brief written explanation gives the AO a reason to approve full reimbursement rather than cap you at the constructed cost.

Attaching the Worksheet in DTS

Once the form is complete, attach it to your DTS authorization as a substantiating document before routing for approval. Drag and drop the file or use the upload function inside DTS.¹ Attach it to the authorization, not just the voucher, because the Authorizing Official needs the cost comparison in hand before approving the trip. If you’re filing a manual travel voucher instead of using DTS, attach the signed worksheet to your DD Form 1351-2.

What the AO Does With It

The Authorizing Official uses the worksheet to decide one of two things: approve your requested mode with full reimbursement, or approve it with reimbursement capped at the constructed cost. The worksheet informs that call; it does not override the AO’s authority under the JTR.⁷

Full Reimbursement

If the AO determines your POV use benefits the government, maybe you’re carrying equipment, traveling with other personnel, or the commercial schedule doesn’t fit the mission, you’ll be reimbursed for actual mileage, per diem for all travel days, and associated expenses like tolls and parking.

Limited Reimbursement

If the AO decides the alternate mode is not to the government’s advantage, transportation reimbursement is capped at the mileage allowance. DTS automatically denies POV-related expenses such as TDY-area parking and tolls. Per diem is affected too. You are only authorized per diem for the number of travel days the authorized mode would have required. If flying would have taken one day but driving takes three, you must zero out per diem on the extra two days.⁷

Zeroing out per diem in DTS is not as simple as it sounds. DTS marks extra travel days as “in transit” and automatically pays a meals and incidental expenses allowance on those days. To override that, either update your itinerary to include each stopover location and change the per diem status, or adjust your TDY arrival and departure dates to show the extra days at the TDY location and manually set lodging, lodging allowed, and M&IE allowed to $0.00 for each unreimbursable day. Skip this and the AO will send the voucher back.

OCONUS Trips and Fly America

International or OCONUS travel adds a layer. When the constructed airfare involves a route covered by the Fly America Act, the government-authorized flight must use a U.S.-flag carrier. A codeshare between a U.S. and foreign airline complies only if it’s booked under the U.S. carrier’s designator and flight number.⁸

If a Fly America exception applies, for example under an Open Skies agreement, you’ll need documentation beyond the worksheet: a signed agency Fly America exception form, a detailed itinerary from a travel agent or online booking tool, and search results showing all available flights at the time of booking that support the claimed exception. Ticket price and personal convenience are not valid grounds for a waiver.

Mistakes That Get Worksheets Rejected

Most rejections come from a small set of avoidable errors. Using a fare quote from a commercial booking site instead of the GSA City Pair tool is the fastest way to get sent back. Pulling mileage from anything other than DTOD is another reliable trigger. Uploading the worksheet only with the voucher, so the AO never saw it before the trip, creates an approval problem after the fact.

Less obvious but just as damaging: failing to zero out per diem on extra driving days after a limited reimbursement decision, leaving passengers off Line 3G when colleagues shared the vehicle, and using the YCA fare when a cheaper _CA fare was available. Any of these can lead to a recoupment during a post-payment audit, with money clawed back from your paycheck after you thought the trip was settled.

1
Defense Travel Management Office. Constructed Travel
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Defense Travel Management Office. Policy Update on Constructed Travel Worksheet and Mileage Requirements
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General Services Administration. City Pair Program
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General Services Administration. Government Airfare Types
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General Services Administration. Per Diem Rates
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General Services Administration. Privately Owned Vehicle (POV) Mileage Reimbursement Rates
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Defense Travel Management Office. Guide: Completing a CTW for Authorizations
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General Services Administration. Fly America Act