# Transportation Engineering Expert

> Expert-level transportation engineering covering highway design, traffic flow, intersection design, pavement design, traffic impact studies, and public transit.

- Skill: `luokai0/transportation-engineering-expert` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add luokai0/transportation-engineering-expert`
- Raw SKILL.md: https://api.skillmd.com/api/skills/luokai0/transportation-engineering-expert/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: luokai0 (https://skillmd.com/u/luokai0)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/luokai0/transportation-engineering-expert

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# Transportation Engineering Expert

## Before Starting
1. Highway design or traffic operations?
2. New facility or existing system analysis?
3. Urban or rural context?

## Core Expertise Areas

### Traffic Flow Theory
Flow, speed, density: q = k times u, fundamental flow relationship.
Greenshields model: linear speed-density relationship, parabolic flow-density.
Capacity: maximum sustained flow rate, varies by facility type.
Level of service: A through F rating of traffic operations quality.
HCM: Highway Capacity Manual, standard methods for capacity and LOS analysis.

### Highway Geometric Design
Horizontal alignment: tangents and circular curves, superelevation.
Stopping sight distance: based on design speed, reaction time, braking distance.
Vertical alignment: grades and crest and sag vertical curves.
Cross section: travel lanes, shoulders, medians, clear zones, slopes.
Design speed: governs all geometric design elements.

### Intersection Design
At-grade intersections: signalized, stop-controlled, yield-controlled.
Signal timing: cycle length, phase splits, offsets for coordination.
Roundabouts: yield at entry, continuous flow, fewer conflict points than signals.
Interchange types: diamond, cloverleaf, directional for grade separation.

### Pavement Design
Flexible pavement: asphalt surface on granular base, AASHTO design method.
Rigid pavement: concrete slab on base, controls deflection and cracking.
ESAL: equivalent single axle load, accounts for different vehicle weights.
Pavement condition: IRI, PCI, distress surveys for maintenance planning.

## Best Practices
- Collect actual traffic counts before designing improvements
- Check sight distance at all critical locations
- Design for design year traffic not just current conditions
- Consider pedestrian and bicycle needs in all transportation design

## Common Pitfalls
| Pitfall | Fix |
|---|---|
| Ignoring pedestrians in signal timing | Include pedestrian crossing time in phase lengths |
| Insufficient sight distance on curves | Check both stopping and passing sight distance |
| Underdesigned pavement for actual trucks | Use actual axle load data for ESAL calculations |
| Wrong LOS method for facility type | Use HCM method specific to facility type |

## Related Skills
- structural-engineering-expert
- hydraulics-expert
- construction-management-expert