Activity durations and logic: the mechanical rules, agency by agency
These are the requirements a reviewer meets first, because they are the ones a schedule file answers on its own. A duration cap needs no correspondence to decide. A ban on start-to-finish relationships is a column in the relationship table. A rule against open ends is a count of predecessors and successors. None of them needs anyone's opinion about the work.
They are also where the sixteen public-agency documents read for this site disagree most concretely. Duration caps run from 15 to 30 days, in three different units. Two agencies permit exactly one relationship type; one permits three; one bans one; several say nothing. One agency prohibits constraints as a class; another requires two of them by name.
The comparison hub sets out each agency's whole requirement. This page follows the mechanics. For what the mechanics do — what a lag changes in a calculation, how a constraint interacts with a backward pass, the difference between total and free float — see lags and leads, schedule constraints and total float and free float. This page stays on what the documents demand.
Part one: duration limits
Read the unit as carefully as the number. Working days, workdays and calendar days are three different bases, and a 20-calendar-day cap is tighter than a 20-working-day one.
| Agency | Lower bound | Upper bound | Unit | Clause |
|---|---|---|---|---|
| ADOT | 1 day | 15 | working days | §108.03 |
| WisDOT | 1 | 15 | working days | §108.4.4.3 |
| NYSDOT | — | 15, excepting submittal and procurement activities unless the Engineer permits otherwise | work days | Item 639 F.1(h) |
| WVDOH | — | 15, except non-construction activities; longer ones kept to a minimum and subject to review | working days | §108.3.1.4 |
| CDOT | — | 15 days of work unless the Engineer approves; a series totalling five workdays or less may be grouped into one | days of work | 108.03(b) |
| PennDOT | A 5-day fineness floor: detail is limited where possible to a minimum 5-day activity | Activities over 15 are limited to a minimum | working days | 689.3(b)3 |
| MnDOT (CPM) | 5 | 20 | working days | §1803.3B.2 |
| MnDOT (bar chart) | 1 | 15 | working days | §1803.2B.1 |
| Caltrans | 1 | 20, unless otherwise authorized | working days | §8-1.02C(2)(10) |
| VDOT | — | 20, unless the Engineer accepts otherwise | work days | II.2.A(6)(c) |
| TxDOT | — | 20 unless agreed; each work activity also carries an estimated production rate per working day | working days | 5.2, 5.4 |
| UFGS 01 32 01.00 10 | — | Non-procurement original durations not to exceed 20 workdays or 30 calendar days | both, in one sentence | §3.3.2 |
| NJDOT | 1 workday | 30 for construction activities, without the Resident Engineer's agreement | days | 153.03.01 |
| SCDOT | — | 30 original duration; an activity past 30 days of actual duration without further cost is ended and broken up | calendar days | Activities, Monthly Updates |
| MDOT SHA | Submittal review activities no shorter than 30 days | No cap. Anything over 10 work days is explained in the narrative each time it occurs | work days | §109.03.01.02(d), (e) |
| WSDOT | — | No numeric cap. Durations are to be reasonable for the work and detailed enough that daily progress can be evaluated | working days | 1-08.3(2), items 3–5 |
| Ohio DOT | — | 20 without the Engineer's approval; maintenance of traffic, erosion control and similar items may not run as single activities to the Completion Date | working days | 108.03.A |
Three of these are not caps at all, and the difference matters. MDOT SHA sets a narrative trigger at 10 work days: a long activity is permitted and has to be explained. WSDOT sets a standard — reasonable, and fine enough for daily evaluation — with no number attached. Ohio attaches the rule to a class of work rather than to a number of days, naming the items that most often become a single bar spanning the job.
And UFGS states two numbers in one sentence. §3.3.2 reads: "Non-procurement activities Original Durations (OD) are not to exceed 20 workdays or 30 calendar days." The reading that makes both operative is one limit selected by the activity's calendar — 30 where the calendar works all seven days, 20 otherwise. Reading it as both makes the second number unreachable; reading it as whichever is larger makes the first decorative. The clause does not say which.
ADOT attaches something no other agency does. §108.03 lets the Engineer call for the working behind any duration, naming four inputs: estimated manpower, equipment, unit quantities and production rates. A schedule file carries none of those, so the cap is checkable from the export and the justification is not. TxDOT's 5.4 comes closest by requiring an estimated production rate per working day on each work activity.
Part two: relationship and lag restrictions
| Agency | Relationship types permitted | Leads and lags | Clause |
|---|---|---|---|
| PennDOT | Finish-to-start only. A single start and a single finish activity for the schedule; every other activity carries at least one predecessor and one successor | Lag and lead incorporated as a separate activity. Redundant relationships not to exceed 5 percent of the total | 689.3(b)3 |
| WisDOT | Finish-to-start only | No leads and no lags | §108.4.4.3 |
| VDOT | Finish-to-start, start-to-start and finish-to-finish, which excludes start-to-finish by omission | Lag prohibited unless the Engineer permits it | II.2.A(9)(a), (9)(e) |
| NJDOT | Written from both ends: a start takes a start-to-start or finish-to-start predecessor; a completion takes a finish-to-start or finish-to-finish successor. Start-to-finish is not used | Not restricted in the clauses read | 153.03.01 |
| CDOT | Start-to-finish prohibited without the Engineer's approval | Negative lags prohibited; lags over 10 workdays prohibited, both without approval | 108.03(b) |
| NYSDOT | Not restricted by type in the clauses read | Lag may not exceed 10 days; negative lag prohibited | Item 639 F.1(i) |
| UFGS | Start-to-finish prohibited. Leads (negative lags) prohibited | Lags must be reasonable as determined by the Government, and not used in place of realistic durations, to absorb or create float artificially, or to replace proper logic | §3.3.16 |
| MDOT SHA | Finish-to-start generally guides the sequence; other types explained in the narrative | Negative lag is not used | §109.03.01.02(d) |
| SCDOT | Not restricted by type in the clauses read | Negative lag not used; lag minimised in favour of an activity standing for it | Schedule Details |
| MnDOT | Not restricted by type in the clauses read | Lags and leads need the Engineer's agreement in advance and may be required to be replaced by an activity; the reason for each goes in the narrative | §1803.3A.4, §1803.3C.1 |
| TxDOT | A predecessor and a successor for each activity | Not restricted in the clauses read | 5.3 |
| ADOT | The schedule shows the interrelationships among activities; no type restricted | Not addressed | §108.03 |
| Caltrans | Not restricted by type in the clauses read | Not established | — |
| WSDOT | Precedence diagramming method on Types B and C | Not restricted in the clauses read | 1-08.3(2)B |
| WVDOH | Criterion 10 fixes one specific relationship: Notice to Proceed follows Project Award by a stated lag — 30 days ordinarily, 7 where the Contract carries an incentive/disincentive clause | — | §108.3.2 |
Pennsylvania goes furthest in two directions at once. It permits one relationship type rather than prohibiting one, and it removes lag from the relationship entirely by making it an activity with a duration, an ID and a calendar. A ten-day lag is a number in the relationship table that a reviewer scrolling the activity list will never see; a ten-day activity named for what happens during those ten days is in the list, carries a calendar and can be progressed. MnDOT and SCDOT push the same way more softly — each prefers an activity to a lag without mandating it.
The five percent cap is the only ratio in this family of documents. 689.1 defines a redundant relationship as a link also represented by a parallel path, removable without affecting the logic or the calculations. Every other numeric rule on this page is absolute; a percentage of total relationships scales, so the same rule binds a 300-activity network and a 3,000-activity one at the same proportion. Its inputs are entirely inside the file.
Part three: constraints, open ends, and out-of-sequence progress
| Agency | Constraints | Open ends | Out-of-sequence progress |
|---|---|---|---|
| CDOT | Prohibited as a class without the Engineer's approval | Prohibited — and defined broadly: an activity whose only predecessor tie is start-to-start, or whose only successor tie is finish-to-finish, counts as open-ended | Retained logic mandated where Primavera is used |
| UFGS | Artificial float constraints such as zero free float or zero total float prohibited; mandatory constraints that ignore or affect network logic prohibited; no constrained dates beyond those the section specifies | Exactly two permitted: the first activity has no predecessor, the last has no successor | Permitted only case by case with the Contracting Officer's approval, with logic corrections proposed before the update and the condition addressed in the narrative |
| NJDOT | Constraint dates only on Completion and interim completion milestones, which must exist as finish milestones carrying a late finish constraint | Every activity except the project start and completion milestones carries predecessors and successors | Not addressed in the clauses read |
| PennDOT | Required in two places: Notice to Proceed takes a Start On or Start On or After; Project Completion takes a Finish On or Finish On or Before. Contract interim milestones take soft constraints and a seven-day no-holiday calendar | Single start and single finish activity; everything else tied both ways | Not addressed in the clauses read |
| VDOT | Limited to milestones the Contract specifies. Start On, Finish On, Mandatory Start and Mandatory Finish prohibited outright | The Make Open-Ended Activities Critical option must be unmarked | Retained Logic required as a declared setting |
| WisDOT | Limited to contractual constraints; the review guidance separately directs that the project Must Finish By constraint be removed | Not restricted by a numeric rule in the clauses read | Not addressed in the clauses read |
| MDOT SHA | Used only where the Contract defines the restriction | Every activity carries at least one predecessor and one successor, except milestones and the first and last activity | Retained logic stated three times in the book; a condition unresolved 30 days after the activity started is corrected by formal revision |
| NYSDOT | Any constraint the Engineer in Charge has not authorized in writing is a ground for immediate rejection | An activity with no predecessor, or none with no successor, excepting the first and last, is a ground for immediate rejection | Actual dates strictly after the data date are a ground for immediate rejection |
| MnDOT | The reason and purpose of each constraint goes in the narrative | At least one predecessor except the first, at least one successor except the last | Not addressed in the clauses read |
| WSDOT | Restraints permitted, but not so as to alter the network's logic or the critical path. On Type C, fixed constraints are identified on the activity listing with a written reason for each | Not restricted by a numeric rule in the clauses read | Not addressed in the clauses read |
| SCDOT | An explanation of each constraint goes in the narrative | A predecessor except the first, a successor except the last | Retain logic required, progress override not permitted; out-of-sequence work and failed starts explained individually |
| TxDOT | Not restricted in the clauses read | A predecessor and a successor for each activity | Not addressed in the clauses read |
| Caltrans | Not restricted in the clauses read | Not established | Not established |
| ADOT | Not addressed | Not addressed | Not addressed |
| WVDOH | Criterion 15 of §108.3.2 governs which constraints are permitted | Not restricted by a numeric rule in the clauses read | §108.3.2 governs how progressed activities are recalculated |
Colorado's open-end definition is the one that changes an answer. An activity whose only forward tie is finish-to-finish has nothing driving its finish through to what follows it, and an activity whose only backward tie is start-to-start has nothing driving its start from what precedes it. A check that counts relationships per activity passes both; a check written to CDOT's definition does not. The two produce different findings on the same file.
Two agencies contradict each other outright on one field. WisDOT's review guidance directs that the project Must Finish By constraint be removed; VDOT's Category III provision requires one, equal to the Contract Completion Date. Same setting, same file, opposite instructions. Nothing resolves that except the contract that governs the project. UFGS §3.3.8.2 takes a third position again, requiring the last activity to be a finish milestone constrained to the Contract Completion Date so that an early finish shows positive float and a late finish shows negative float on the longest path.
Network-shape rules: counts and proportions
Four documents state a rule about the network as a whole rather than about any one activity, and these need the population counted rather than a row read.
| Agency | Rule | Clause |
|---|---|---|
| Caltrans | At least 50 and not more than 500 activities, unless otherwise authorized. Not more than 50 percent of baseline activities critical or near critical — with near critical defined as total float above the critical path's but not more than 10 working days | §8-1.02C(2)(5), (6); §1-1.07B |
| MnDOT | Not more than 20 percent of activities critical, and not more than 30 percent near-critical, unless otherwise authorised | §1803.3B.2 |
| WVDOH | At least ten activities per million dollars of Contract, and not more than three hundred | §108.3.1.4 |
| PennDOT | Redundant relationships not to exceed 5 percent of the total number of relationships | 689.3(b)3 |
| CDOT | Near critical defined as total float of five days or fewer, or as the Engineer defines | 108.03(a) |
Note that Caltrans and CDOT define the near-critical band at different widths — 10 working days against 5 days — and MnDOT states a cap without printing a band in the clause read. A near-critical share is not comparable between agencies unless the band is stated with it.
What this project does with these clauses
Almost everything on this page is decidable from an imported file: durations and their units, relationship types, lag values and signs, predecessor and successor sets per activity, constraint types and dates, calendar assignment, activity counts, and the float that follows from the network. This project computes and reports them and cites the clause — see what the engine does, how it works and reading a report.
Four things it does not do.
- It does not decide whether an approval exists. Most of the caps above are qualified — unless the Engineer approves, without the Resident Engineer's agreement, unless otherwise authorized. Whether an approval was given is a fact about the contract record and not about the file, so a rule that meets one asks for the fact rather than assuming it either way.
- It does not decide whether a duration or a lag is reasonable. UFGS §3.3.16's "lags must be reasonable as determined by the Government" and WSDOT's reasonableness standard are not computations. Where a clause is not a computation, this engine assembles the evidence and states the question for the reviewing authority.
- It does not read every field. Expected Finish dates, constraint times of day and the distinction between a blank lag and a stated zero lag are among the categories named on the limitations page. A check over a field the model does not carry would pass every schedule.
- It states no threshold of its own. Every number on this page belongs to a document, cited. None of them is this project's view of what a schedule ought to contain.
Which of these clauses governs a particular project is a fact about its incorporated contract documents — the edition named, the special provisions, and for several agencies the schedule type or tier the procurement selects.
Related pages
- How the sixteen specifications compare.
- Lags and leads · schedule constraints · total float and free float · schedule calendars.
- P6 schedule options — retained logic, longest path and the settings several of these clauses name.
- Baseline schedule submission · schedule narrative requirements · recovery schedules · time impact analysis requirements.
- Agency detail: CDOT · MnDOT · NJDOT · NYSDOT · PennDOT · UFGS · VDOT · WisDOT · WVDOH.
- Schedule audit checklist · the DCMA 14-point check · glossary · limitations.
Source: web/pages/activity-durations-and-logic.md. Source commit date: 2026-09-11.