Phase: Applied learning · Worked scenarios · Calculations · Audit findings · Document drills
Apply what you've read — scenario by scenario, calculation by calculation
AASHTO/3R for NHS, Caltrans manuals for SHS, design exceptions. Each exercise has a hidden solution — work through your answer before revealing.
I
Scenario 01
NHS project — design standard
Setup
An LPA federal-aid project widens an NHS-classified arterial off the State Highway System. The City Engineer proposes using the City's own locally-developed urban design standards (which differ from AASHTO).
Question
Is this permitted? What are the alternatives?
Solution
Not permitted as-is. LAPM Ch 2 §2.8 and Ch 11: "LPAs are required to use only AASHTO, 3R, and other design standards officially approved for use on NHS projects that are off the SHS. Locally approved design standards are not allowed on NHS projects."
Alternatives:
1. Use AASHTO standards (A Policy on Geometric Design of Highways and Streets — "the Green Book") for the project design. This is the default.
2. Request a project-specific exception. "Caltrans may approve exceptions on a project-by-project basis." The LPA prepares a written justification documenting:
• The non-conforming standard.
• The reason for the deviation (urban context, ROW constraints, etc.).
• Safety analysis showing the alternative provides equivalent or better safety.
• Sign-off by the LPA's responsible engineer.
Submit to DLAE for routing to Caltrans HQ Local Assistance/Design.
3. 3R standards for resurfacing/restoration/rehabilitation — different criteria than full reconstruction. 3R applies to existing-pavement projects.
Key trap: Many cities have locally-adopted standards that conflict with AASHTO. For NHS projects, the AASHTO/3R standards govern unless a project-specific exception is approved IN WRITING before final design.
For SHS projects, Caltrans Highway Design Manual (HDM) governs — not AASHTO, not local standards.
Authority: LAPM Ch 11; LAPM Ch 2 §2.8
III
Audit Finding 01
Read the fact pattern — what's the finding?
Facts
An NHS federal-aid project was constructed with horizontal curve radii below AASHTO minimum for the design speed. No design exception was submitted to Caltrans before construction. The City Engineer signed the plans certifying compliance with applicable standards.
Analysis
What is the finding? What is the exposure?
Finding · Citation · Corrective action
Finding: Non-conforming design on NHS project without approved design exception. Violates LAPM Ch 11.
Exposure:
1. Federal participation risk. The non-conforming portion may be ineligible for federal reimbursement.
2. Liability exposure. Sub-AASHTO geometry without documented justification creates tort liability for the LPA in the event of a related crash.
3. Engineer professional liability. Certifying compliance when the design did not meet AASHTO minimums is a potential professional standards violation for the licensed PE.
4. Future LPA standing. Pre-Award audit finding affecting future federal-aid projects.
Corrective actions:
1. Retroactive design exception — possible but disfavored. LPA prepares the exception justification, safety analysis, and risk acceptance documentation. Submit to Caltrans for review. If approved, partial cure but the timing creates audit findings.
2. Reconstruction — if safety analysis cannot justify the geometry, LPA may need to reconstruct portions to bring to standard. Cost would not be federally reimbursable.
3. Safety mitigation — additional signing, striping, advisory speed reduction. Doesn't cure the standards finding but reduces liability.
Lesson: Submit design exceptions IN WRITING IN ADVANCE for any NHS project deviating from AASHTO. The PE's seal certifies what was reviewed, not what was constructed.
Authority: LAPM Ch 11; AASHTO Green Book
Applied learning · Companion chapter
These exercises apply the procedural framework presented in LAPM Chapter 11: Design Guidance. For the full chapter reference, glossary, and recall quiz, see the deep chapter file.