Highway design workflow: Before starting highway construction, engineers must plan both horizontal alignment (plan view) and vertical alignment (profile/grades). Is this standard practice?

Introduction / Context:
Highway projects require careful alignment design to ensure safety, capacity, drainage, earthwork balance, and cost control. Alignments are fundamental inputs for right-of-way, structures, and construction staking.

Given Data / Assumptions:

• Horizontal alignment specifies tangents and curves in plan.
• Vertical alignment defines grades and vertical curves in profile.
• Design must meet standards for sight distance, superelevation, and drainage.

Concept / Approach:
The standard road design process develops a coordinated pair of alignments. The horizontal plan affects curvature and superelevation, while the vertical profile affects grades, crest/sag curves, and earthwork. Iterative design ensures both alignments satisfy criteria simultaneously.

Step-by-Step Solution:

Verification / Alternative check:
Check a typical plan set: you will find plan and profile sheets, cross-sections, and alignment tables confirming both alignments are always planned.

Why Other Options Are Wrong:

Common Pitfalls:
Designing horizontal curves without matching vertical sight distances; ignoring drainage implications of long sags or crests; failing to iterate earthwork balance.

Final Answer:
Correct