Road Alignment Principles MCQ with answer and solution

Concept

Road Alignment Principles

Formula

N/A

Step-by-step solution

1. Analyze Statement 1 and confirm that obligatory points are control points a road alignment must pass through or avoid. 2. Analyze Statement 2 and recognize that a straight alignment is not always the most economical due to terrain and earthwork costs. 3. Conclude that Statement 1 only is correct and select Option (a).

Explanation

Option A (1 only) is correct because statement 1 accurately defines obligatory points as locations a road must either pass through (like key towns or bridge sites) or strictly avoid (like marshy areas or protected sites). Statement 2 is incorrect because a strictly straight route is not always economical; in difficult terrain or around natural obstacles, forcing a straight path can drastically increase construction and earthwork costs compared to a slightly curved alignment.

Shortcut

To remember road alignment principles, use the rule "Obligatory = Obey, Straight ≠ Always Best": - Obligatory Points (Obey): Mandatory control points that the road alignment must pass through (e.g., major towns, bridges) or strictly avoid (e.g., marshy land, heritage sites). - Terrain & Economy: A straight line is NOT always the most economical, as difficult terrain or obstacles significantly increase earthwork and construction costs.

Common mistake

A common mistake is selecting option C by assuming that a straight alignment is always the most economical route regardless of terrain. In reality, forcing a straight road through difficult terrain or mountainous areas requires excessive cutting, filling, or tunneling, which significantly increases construction costs compared to a slightly curved alignment. Another frequent mistake is selecting option D by misunderstanding the definition of obligatory points, which correctly include control locations that an alignment must either pass through or strictly avoid.