TxDOT Item 500 Mobilization: Bid Code Spec, Pricing and Payment Schedule Requirements
Item 500 isn't a physical item, there's nothing to build, no material to source. It pays for establishing and removing offices, plants, and facilities, and moving personnel, equipment, and supplies to and from the project. The real complexity isn't in the work, it's in how you get paid for it. Mobilization doesn't arrive as a lump sum up front, it releases across seven separate milestones tied to how much of the rest of the contract is earned, and two of those milestones share the same payment cap, which means hitting the second one doesn't always release any new cash. This covers the 5 bid codes that show up most often across recent TxDOT lettings, what separates standard mobilization from callout and emergency mobilization, and exactly how the payment schedule actually works.
TxDOT Item 500 Bid Code Variants: What Determines Pricing
Item 500 covers three genuinely different things, not three sizes of the same thing:
Standard mobilization. A single lump sum for the entire project, covering all offices, plants, facilities, and the personnel, equipment, and supply moves needed to begin and complete work on the contract. Priced once, paid out across the milestone schedule below.
Callout mobilization. Not a lump sum, a per-request charge.
"Mobilization for callout work will be paid for each callout work request."
Every time you're dispatched for callout work, that's a separate mobilization payment, priced far smaller than standard mobilization because it's covering a single trip, not an entire project's setup.
Emergency mobilization. Also per-request, but with a real standing obligation attached:
"For Contracts with emergency mobilization, provide a person and method of contact available 24 hr. per day, 7 days per week, unless otherwise shown on the plans."
That 24/7 standby requirement is why emergency mobilization prices above callout mobilization in this data, roughly 25 percent higher. You're not just pricing the trip, you're pricing being ready to make it at any hour.
Don't compare standard mobilization's price directly against callout or emergency. They look like wildly different numbers, and they are, but not because one is bigger scope than the other. Standard mobilization is priced once for the whole project. Callout and emergency are priced per event, and a single project might trigger either of them many times over its life. Comparing the averages side by side without that context is comparing a project-wide lump sum to a per-trip fee.
TxDOT Item 500 Pricing: Key Takeaways
- Mobilization isn't paid up front. It releases across seven milestones tied to bond and insurance presentation, facility setup, and how much of the rest of the contract is earned.
- Two milestones share the same payment cap. Both the 5 percent and 10 percent construction-progress milestones cap at "10% of the total Contract amount." If that cap is what's binding, reaching 10 percent progress may not release any money beyond what the 5 percent milestone already paid.
- The final 3 percent can be held back well past substantial completion. It's tied to submittals, final quantities, and any vegetative establishment, maintenance, test, or performance period succeeding, and on extended-maintenance contracts specifically, it's withheld a flat 6 months after final acceptance.
- Material on hand doesn't count toward your progress thresholds. Stockpiling materials early doesn't accelerate mobilization payment, only earned construction items do.
- Mobilization doesn't scale up with added scope. It's calculated on the base bid only and isn't paid separately on additive alternates added to the contract later.
Cost Factors for TxDOT Item 500 Mobilization
Cost Factors That Vary by Bid Code
Work through these one code at a time. They're what makes 500-7033 a different number than 500-7001.
- Which mobilization type you're pricing. Standard, callout, and emergency aren't tiers of the same service, they're different pay structures entirely, one lump sum against two per-event charges. Confirm which one a given plan sheet is asking for before pricing off a code you've used on a different job.
- The 24/7 standby requirement, on emergency mobilization specifically. That's a real staffing cost, someone reachable at any hour, every day, for the life of the contract, unless the plans say otherwise. It's why emergency mobilization prices above callout in this data.
- How many callout or emergency events the contract is likely to trigger. Since both are paid per request rather than once, the real cost exposure isn't the per-event price alone, it's that price multiplied by how often you expect to get called.
Cost Factors That Apply to Every TxDOT Item 500 Bid Code
These don't separate one mobilization type from another. They sit under all of them.
- Bonds and insurance are required to perform mobilization at all, on every type.
"Bonds and insurance are required for performing mobilization."
- The scope is the same three things, regardless of type. Establish and remove offices, plants, and facilities. Move personnel, equipment, and supplies to and from the project. Every mobilization payment, standard or per-event, is compensating some version of that same underlying work.
- Notice timing is defined precisely, for emergency work. The clock starts at "the transmission time of the written notice or notice provided orally by the Department's representative," not whenever you happen to receive or act on it.
TxDOT Item 500 Payment Terms: What Counts Toward Payment, and What Doesn't
Item 500 doesn't bundle other items into itself the way a physical construction item does, there's no materials list, no subsidiary work folded in. What matters here is what does and doesn't count toward releasing your mobilization payment.
"Adjusted Contract amount" is not the full contract value, and that distinction runs through every milestone below.
"The adjusted Contract amount will be calculated as the total Contract amount less the lump sum for mobilization."
Every progress percentage in the payment schedule is measured against the contract minus mobilization itself, not the raw total.
Material on hand doesn't count as earned progress, specifically for this item.
"Material on hand will not be considered as a construction item earned when calculating mobilization payment."
On many contracts, stockpiled material counts toward earned value. Here, it explicitly doesn't, for the purpose of triggering mobilization payments specifically.
Mobilization doesn't apply to additive alternates.
"Mobilization is calculated on the base bid only and will not be paid for separately on any additive alternate items added to the Contract."
If scope gets added later, don't expect a second mobilization payment to come with it.
Callout and emergency mobilization skip the milestone schedule entirely. Both are paid per request, on presentation of a paid invoice for bonds and insurance, not through the progressive percentage structure that governs standard mobilization.
TxDOT Item 500 Payment Schedule: How and When Mobilization Actually Gets Paid
This is the real substance of Item 500. Standard mobilization releases across seven milestones, and the caps at two of them overlap in a way that's easy to miss until it affects your cash flow.
The overlap worth catching: the 5 percent and 10 percent construction-progress milestones both cap at "10% of the total Contract amount." If your mobilization lump sum is priced high relative to the total contract, a common bid strategy to bring cash in earlier, that total-contract cap is likely what's binding at both milestones, not the mobilization percentage. That means going from 5 percent to 10 percent construction progress can release zero additional mobilization payment, even though the milestone table makes it look like a jump from 75 percent to 90 percent of your lump sum. Model this against your own mobilization bid amount before assuming each milestone brings new cash.
The remainder can run well past substantial completion. 97 percent is paid at final acceptance, but the last 3 percent waits on submittals, final quantities, and any vegetative establishment or performance period succeeding. Vegetative establishment periods in particular often carry their own multi-month survival window, which means the true close-out of your mobilization payment can trail physical completion by a season or more. On extended-maintenance contracts, that wait is a defined 6 months, not open-ended.
Pricing and Cash Flow Considerations
- Model your mobilization bid against the total-contract caps, not just the percentage-of-lump-sum figures. A high mobilization bid relative to total contract value can hit the same ceiling at two different milestones, flattening your expected cash flow curve.
- Don't count material on hand toward your own internal progress tracking for this item specifically. It won't move your mobilization payment even if it moves other parts of your billing.
- Plan financing around the 3 percent holdback separately from substantial completion. If the contract has a vegetative establishment or extended maintenance period, that final piece of mobilization is a real, dated liability, not a rounding error.
- Price emergency mobilization's standby requirement as a real staffing cost, not just a markup over callout, someone has to actually be reachable 24/7 for the contract's duration.
TxDOT Item 500 Bid Item Pricing Data
Average unit price across TxDOT lettings over the last 24 months. Each code links to its full pricing page, where you can see the spread by competitor, by district, and by quantity band.
Pricing Analysis: Key Cost Comparisons Across TxDOT Item 500
Two codes here share the identical description and price nowhere close to each other. 500-6001 and 500-7001 are both plain "MOBILIZATION," and one averages $11,727,626 against the other's $768,495, a 15x spread. Same pattern on the callout side: 500-6033 and 500-7002 are both "MOBILIZATION (CALLOUT)," at $1,467 and $1,126. This isn't inconsistent pricing for the same thing, it's what happens when a lump-sum item's price is set almost entirely by project size rather than by anything the code description captures. Two different letting periods, two different mixes of project scale feeding into each code's average, and standard mobilization in particular has no ceiling tied to the item itself, only to the size of the contract it's mobilizing for. Don't treat either number as "the" mobilization price. Size your own bid against your project's actual setup costs and the cash-flow schedule above.
The useful comparison here is between callout and emergency mobilization specifically, since they're the only two codes priced on the same basis, per request. Standard mobilization isn't comparable to either, it's a different unit entirely, a one-time lump sum against a per-event fee.
Emergency mobilization prices about 25 percent above callout, and the 24/7 standby requirement is the likely reason.
Both are triggered per event rather than paid once, so the entire gap between them is attributable to what emergency work specifically demands, availability at any hour, every day, not a bigger scope of work per trip.
Executing TxDOT Item 500: Avoiding Rework and Ensuring Payment
For whoever's managing the contract. Same spec, stated as things to do. "Rework" doesn't apply in the usual sense here, there's no physical item to redo, so this section focuses on what protects payment and cash flow instead.
Payment Risks Under TxDOT Item 500
- Treating each construction-progress milestone as guaranteed new cash, when the total-contract cap may already be binding from the prior milestone
- Counting material on hand toward internal progress tracking for mobilization specifically, when the spec explicitly excludes it
- Assuming a second mobilization payment on additive alternate scope added later in the contract
- Missing that the final 3 percent depends on vegetative establishment or performance periods succeeding, not just physical completion
Field and Administrative Requirements for TxDOT Item 500
- Paid invoices for bonds and required insurance ready to present as the first payment trigger
- Documented expenditures for plant and facility setup, kept ready for verification
- A named person and contact method available 24 hours a day, 7 days a week, for contracts with emergency mobilization, unless the plans state otherwise
- Notice timing tracked from the actual transmission time of written or oral notice, not from when it's acted on
Pay Application Requirements for TxDOT Item 500
- Track adjusted Contract amount, not total Contract amount, since that's the base every construction-progress percentage in the schedule is measured against
- Submit callout and emergency mobilization invoices per request, not bundled or batched, each event is its own payment trigger
- Confirm whether the contract carries an extended maintenance or performance period early, since that determines whether your final 3 percent is tied to a fixed 6-month date or to variable completion of submittals and performance periods
- Keep prior mobilization payments documented and current, since every milestone payment is calculated net of what's already been paid under this item
Built for people pricing and executing TxDOT mobilization work
Frequently asked questions about TxDOT Item 500
What is TxDOT Item 500, Mobilization?
It's the TxDOT spec covering the cost of establishing and removing offices, plants, and facilities, and moving personnel, equipment, and supplies to and from a project, along with the milestone-based schedule that governs when and how much of that cost gets paid.
Is mobilization paid as a lump sum up front?
No. Standard mobilization is bid as a lump sum but released across seven milestones tied to bond and insurance presentation, facility setup, and how much of the rest of the contract is earned, with the final 3 percent held until submittals, final quantities, and any performance period are complete.
Why might hitting 10 percent construction progress not release any new mobilization payment?
Because the 5 percent and 10 percent progress milestones both cap payment at 10 percent of the total Contract amount. If your mobilization lump sum is large relative to the total contract, that cap can already be binding at the 5 percent milestone, leaving nothing new to release at 10 percent.
Does material on hand count toward mobilization payment milestones?
No. The spec specifically excludes material on hand from being considered a construction item earned when calculating mobilization payment, even if it counts toward other billing.
What's the difference between callout and emergency mobilization?
Both are paid per request rather than as a lump sum. Emergency mobilization additionally requires a person and contact method available 24 hours a day, 7 days a week, which is reflected in a roughly 25 percent higher average price in this data.
Does mobilization get paid again if the contract adds scope later?
No. Mobilization is calculated on the base bid only and isn't paid separately on additive alternate items added to the contract.
When does the final 3 percent of mobilization get paid?
After all submittals are received, final quantities are determined, and any separate vegetative establishment, maintenance, test, or performance period has been successfully completed. On contracts with extended maintenance or performance periods specifically, it's paid a flat 6 months after final acceptance.
Is "adjusted Contract amount" the same as the total contract value?
No. It's the total Contract amount minus the mobilization lump sum. Every progress percentage in the payment schedule is measured against that adjusted figure, not the raw total.
How is Item 500 measured?
By the lump sum or each, as the work progresses, calculated on the base bid only.
Is this pricing data free to use?
Yes. Every bid item pricing page linked above is free, no account needed.