Iowa DOT progress scheduling requirements: Section 1110 and DS-23004
The Iowa Department of Transportation splits its scheduling requirement across two documents, and which one governs a project depends on what the contract documents call for.
The Standard Specifications for Highway and Bridge Construction, Series 2023 carries Section 1110, "Progress Scheduling" — the critical path method clause. It applies, in its own opening words, when the contract documents specify it. Everything else runs on the general progress schedule article, which sat at Article 1108.02, J until DS-23004, Developmental Specifications for Construction Progress Schedule, effective 17 October 2023, replaced all of that article with a new one.
Which text governs. DS-23004 states on its face that developmental specifications prevail over the Standard Specifications, and the Series 2023 preface describes the book as a floor that a particular contract may change through its Supplemental Specifications, its Developmental Specifications and its Special Provisions. So for the general progress schedule, DS-23004 is the later instrument. Section 1110 is untouched by it and stands as printed.
What the two documents require
| Requirement | What the text states | Clause |
|---|---|---|
| Scheduling software | None named, in either document. §1110.01, A states the CPM progress schedule may be hand or computer developed, and points to the principles in the most current issue of AGC's The Use of CPM in Construction. No product appears in Section 1110 | §1110.01, A |
| When CPM applies | When specified in the contract documents. Where a CPM submittal is called for in the proposal form, the successful bidder submits five copies to the Contracts Engineer with the signed contract | §1110.01, A; §1110.02, A |
| General progress schedule | Every project under DS-23004: a preliminary schedule at the preconstruction conference, then three copies of a progress schedule at least 5 calendar days before starting work | DS-23004, J.1 |
| Agency review | For CPM: the Contracting Authority responds within 10 calendar days saying whether the schedule is approved or what corrections are needed. Where revisions are required, the revised CPM schedule is due 10 or more calendar days before the preconstruction conference | §1110.02, B |
| Gate on starting work | No contract work is to be done without a CPM progress schedule approved by the Engineer. Under DS-23004, a failure to supply a satisfactory schedule or revision can hold up progress payments until one is handed over and taken | §1110.04, A; DS-23004, J.6 |
| Update frequency | CPM: the Contractor reviews the schedule with the Engineer biweekly unless otherwise specified, and submits a revised schedule within 5 working days of the review meeting if behind schedule or if the schedule has been modified. DS-23004: joint review with the Engineer at least every 2 weeks, with revised schedules due within 5 business days of a request | §1110.04, B; DS-23004, J.3, J.4 |
| Narrative | Not required as a separate document in either text. The content sits in the network diagram, the numerical tabulation and a legend defining every abbreviation, term and symbol used | §1110.03, A, B, C.2 |
| Revised schedule trigger | CPM: a revised schedule is required if the controlling operation falls 10 working days behind. At 20 working days behind, with completion in the specified time in jeopardy, the Contracting Authority may act under Articles 1102.03, B and 1103.01. DS-23004: completion or intermediate targets delayed 10 working days or more; progress differing significantly from the current schedule such that completion within the contract period is unlikely; or a change order requiring a revision to work sequence or method | §1110.04, D; DS-23004, J.3 |
| Time impact analysis | Not in Section 1110. It appears in the disputed claims article: where a claim seeks a contract extension or other time-related recovery, the claimant submits the schedule that was in effect when the conditions arose, plus a time impact analysis and a detailed narrative identifying causation and the specific calendar dates of each impact claimed | §1109.10, D.6.c |
| Float ownership | Not established. Both the network diagram and the tabulation must carry slack or float per activity in work days, but neither document read here states who owns it | §1110.03, A.2, B.1 |
| Activity durations | No individual activity duration longer than 20 working days unless the contract proposal or the Contracting Authority states otherwise | §1110.03, C.1 |
| Activity numbering | A unique activity numbering system identifying activities by bid item, work item, area, procurement or subcontractor. Where subnetworks are used, no two activities may share a number or a description | §1110.03, C.1 |
| Calendar | A work-days calendar extending the length of the contract plus 25% additional time | §1110.03, A.2 |
| Payment for the schedule | No separate item. The cost of preparing and revising the schedule is included in the bid item for Mobilization; DS-23004 likewise folds the general progress schedule into mobilization | §1110.05; DS-23004, J.7 |
Two documents, two different schedule products
The distinction is not one of detail level but of kind.
DS-23004 asks for a chronologically sequenced bar chart: planned start dates and durations for each item of work, including estimated weather delay days; the controlling item of work shown for every day of the schedule; the intended rate of production for each item; and project staging, required milestones and any project suspensions of 3 working days or longer. There is no relationship logic in that list and no network.
Section 1110 asks for a network diagram with a numerical tabulation. The diagram carries activity description, duration in work days, intended production rates, subcontracted activities with the subcontractor identified, activity location, the critical path noted, numbered event nodes, all restraints noted, slack or float per activity, the work-days calendar, dummy paths noted, and start and completion dates. The tabulation repeats much of that per activity in columns and adds earliest and latest start and completion dates as calendar dates, the Contractor's own intended start and completion dates, and the quantities involved on each activity based on those intended dates.
That column list is the part worth noticing. A tabulation carrying both the computed early and late dates and the Contractor's intended dates states two different things about the same activity, and the difference between them is visible without recomputing anything.
Payment withheld for departing from the critical path
Most of the specifications read for this site attach consequences to a late or missing schedule. §1110.04, C attaches one to how the work is actually sequenced: where work departs from the currently approved CPM schedule by running the critical path out of its logical order, the pay items for the affected activities go unpaid until a revised schedule is handed in and the Engineer approves it.
The clause also gives the schedule a second job. §1110.04, A makes the items in the activities on the denoted critical path the controlling operations, and it is against those that working days are charged. On a working-day contract, that ties the contract clock to the critical path the schedule declares, which is a heavier role than a monitoring document usually carries.
A lettering discrepancy worth checking on your own contract
DS-23004 replaces all of Article 1108.02, J. In the printed Series 2023 book, Article 1108.02, J is "Schedule of Staging" — the progress schedule is not at that letter in the printed text. Section 1110 separately cross-references Article 1108.02, K, which in the printed book is "Accelerated Work Schedule".
This page reports that as read rather than resolving it. Iowa maintains its specifications online as well as in print, subsequent Supplemental and Developmental Specifications modify the book, and the article lettering in the instrument your contract incorporates may not match the printed 2023 edition. Confirm the lettering against the specification library named in your contract before citing 1108.02, J to anyone.
What this page does not tell you
- It does not tell you which clauses govern your project. Section 1110 applies only when the contract documents specify a CPM progress schedule, and the general article is modified by whichever developmental and supplemental specifications and special provisions were in force at letting. An agency name alone does not establish which clauses apply.
- Two documents were read: the printed Series 2023 book and DS-23004. Later revisions, other developmental specifications and any project special provisions were not read for this page. Their absence here is not a finding that they do not exist.
- Float ownership is marked not established because nothing was read on it. Both texts require float to be shown per activity; neither states who owns it.
- The deadlines above are facts about submissions. A schedule file carries a data date; it does not carry the date it was handed over, the date of contract award or the date of a review meeting. This project does not check them, and its silence about them is not a statement that they were met.
- AGC's The Use of CPM in Construction was not read. §1110.01, A incorporates its principles by reference; this page reports that the reference exists and nothing about its content.
- There is no rule pack behind this page. These pages are readings of published specifications, not implemented checks. What this project implements is listed in the conformance catalogue; the internal answer table, which is not published, records what was refused.
- This project computes and reports; it does not decide submissions. It states what an imported schedule contains and checks it against the clauses cited. Entitlement, excusability and whether a schedule is adequate are not questions it answers. The reviewing authority decides acceptance.
Related pages
- How state DOT scheduling specifications compare.
- Neighbouring agencies read the same way: Minnesota, Wisconsin, Michigan.
- Baseline schedule submission, recovery schedules and time impact analysis.
- Activity durations and logic — the 20-working-day limit in context.
- Glossary — slack, float, restraint, controlling operation.
- What the engine does and limitations.