Which sequence correctly describes the stages of highway route selection and field investigations from initial study to final design geometry?

Introduction / Context:
Highway location proceeds through progressively detailed stages. Early studies identify feasible corridors; subsequent field work refines these into surveyed alignments with precise horizontal and vertical geometry for design and construction.

Given Data / Assumptions:

• Standard sequence: reconnaissance → preliminary location/trace cutting → detailed surveys and design.
• Terrain and constraints are evaluated at each step.

Concept / Approach:
Reconnaissance screens alternatives and selects a general route using maps, satellite imagery, and brief field visits. Trace cutting physically marks the centerline on ground to assess practicality and local obstacles. Detailed surveys (plan and profile, cross-sections, benchmarks) then deliver the data needed to finalize curves, grades, and earthworks.

Step-by-Step Solution:
Stage 1: Reconnaissance → choose general alignment corridor.Stage 2: Trace cutting → mark and walk the line; adjust locally as needed.Stage 3: Detailed surveys → fix geometries, staking, and control for design.

Verification / Alternative check:
This sequence is standard in transportation engineering textbooks and aligns with agency procedures worldwide.

Why Other Options Are Wrong:

• A–C are each correct but incomplete when taken alone; only D captures the full, ordered process.

Common Pitfalls:
Skipping control establishment and benchmarks before detailed profiles; making large alignment changes after detailed surveys, which increases cost and time.

Final Answer:
All of the above