Engineering Insights · QA/QC

What Should Be Checked Before a 90% PS&E Submittal?

Plans, Specifications & Estimate—PS&E—should function as one coordinated construction package. At 90%, the design should be mature enough for a reviewer to test completeness, consistency, constructability and release readiness without relying on major unresolved assumptions.

Key Takeaways

The 90% review is a technical and coordination gate, not a proofreading pass.
Plans, specifications, quantities and estimate should describe the same work.
Review interfaces between disciplines, stages and sheets—not only individual details.
Resolve prior comments and document QA/QC decisions before final release.
An Independent Technical & Constructability Review can provide a fresh, defined check without transferring responsible charge.

Why the 90% Milestone Matters

The 90% submittal is typically late enough that core design decisions should be established, yet early enough to correct significant issues before final release. Exact milestone requirements vary by client and agency. The review plan should therefore follow the governing quality plan, contract, standards and submittal checklist rather than assuming one universal definition of 90%.

Design Completeness

Confirm that the package covers the authorized scope and that unresolved decisions are clearly identified. Major geometry, profiles, drainage, utilities, traffic elements, staging and project limits should be developed to the level expected by the owner. Placeholder notes and “to be determined” items need owners, due dates and a plan for closure.

Cross-Sheet Consistency

Compare plan views, profiles, details, schedules, quantities and notes. Check that stationing, offsets, elevations, pay limits, material callouts and references agree. Trace representative features across the set—from existing condition through removal, construction, staging and final configuration—to expose gaps that are easy to miss during a sheet-by-sheet review.

Existing Conditions and Base Mapping

Verify the survey, right-of-way, control, utilities, drainage features and visible improvements used for design. Identify information based on records or assumptions. Confirm that later survey or field-verification updates were incorporated consistently and that uncertainty affecting construction is communicated appropriately.

Geometry and Stationing

Check alignments, station equations, curve data, dimensions, offsets, match lines and ties to control. Review transitions between project limits and existing facilities. Geometry should support construction layout and agree across plan, profile and detail views.

Quantities and Engineer’s Estimate

Trace pay items to plan limits, details and calculation support. Look for missing work, double counting, unit inconsistencies and items whose quantity basis is unclear. Confirm that estimate items map to the quantity summary and applicable specifications. Review unusual or high-risk items deliberately. Escalation, contingency and allowances should follow the owner or agency process rather than a generic formula.

Specifications

Confirm that referenced standard specifications, special provisions and project-specific requirements align with the plans and estimate. Remove provisions that do not apply. Resolve plan/spec conflicts and verify that materials, testing, measurement and payment language support the intended work. Defined responsibilities should be consistent across the contract documents.

Notes, Legends and Details

General notes should be relevant, current and nonconflicting. Legends should define symbols and abbreviations actually used. Details should match the proposed condition, dimensions and materials. Verify that callouts lead to the right sheet and detail and that repeated details do not provide competing instructions.

Traffic Control and Staging

Review sequence, work-zone limits, lane and shoulder impacts, closures, detours, access, temporary markings, devices and transitions. Confirm that each stage can be constructed and that interim conditions connect logically. Pedestrian, bicycle, transit, emergency and property access should be addressed where applicable.

Signing, Striping, Signals and ITS

Check removal and installation limits, sign codes, striping patterns, stationing, offsets and quantities. For signals and ITS, review equipment, poles, cabinets, detection, conduit, pull boxes, communications, power, wiring and interfaces with existing systems. Verify that schedules, notes, details and quantities agree with plan graphics.

Utilities, Drainage and ADA

Review known utility conflicts, relocations, potholing or verification needs and coordination responsibilities. Confirm drainage paths, inlet and pipe information, outfalls and interfaces with staging. Evaluate accessible routes, curb ramps, crossings and temporary pedestrian provisions for geometry and grade consistency.

Constructability and Maintenance

Ask how the work will be built, accessed, sequenced, inspected and maintained. Review equipment access, temporary conditions, excavation conflicts, work-space needs and interfaces with ongoing operations. Consider whether future maintenance staff can safely reach cabinets, structures and other serviceable assets.

Comments, Permits and Coordination

Close prior review comments with documented responses. Confirm that permit requirements, railroad or utility coordination, environmental commitments and outside-agency interfaces are represented as required. Identify items still controlled by another party and how they affect release readiness.

QA/QC Documentation

Maintain marked-up review records, issue logs and evidence of comment disposition consistent with the project quality plan. A check is not complete because a markup exists; comments must be resolved, verified and incorporated. Independent Technical & Constructability Review can add value when the package needs a fresh cross-discipline and construction-focused assessment.

Final 90% Readiness Checklist

Authorized scope is represented and major decisions are closed.
Base mapping and existing conditions are current for the design stage.
Plans, specifications, quantities and estimate agree.
Geometry, stationing, references and match lines are consistent.
Traffic control, utilities, drainage, ADA and discipline interfaces are coordinated.
Previous comments are resolved and documented.
Permits and external coordination items have clear status.
Constructability and maintenance access were reviewed.
QA/QC records show comment closure and verification.
Remaining risks, assumptions and final-stage tasks are explicit.

When to Involve an Independent Reviewer

Independent review is useful when a team wants a defined technical check before a major owner or agency submittal, particularly for compressed schedules, inherited work, multidisciplinary packages or late design changes. The reviewer’s scope, criteria, deliverables and relationship to the Engineer of Record should be documented before review begins.

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Professional Note

Requirements vary by jurisdiction and project. This article provides general engineering guidance and is not a substitute for project-specific review of applicable codes, standards, records, surveys, geotechnical information, utility information or agency requirements.

Sawan Dhaliwal, PE
Licensed Civil Engineer — AZ | CA | MO