History of road engineering: Who is credited with developing road making as a systematic building science leading to the “macadamized” road?

Introduction / Context:
Modern highway engineering evolved through the work of several pioneers. Understanding these contributions helps appreciate why present-day pavements and drainage details look the way they do.

Given Data / Assumptions:

• Question seeks the individual most associated with systematic road making that popularized “macadamized” roads.

Concept / Approach:

John Loudon McAdam introduced a scientifically reasoned method of constructing roads with compacted layers of small, single-sized, angular aggregates on a well-drained formation. His emphasis on drainage and thin, well-compacted layers revolutionized road building in the 19th century and laid the foundation for later bituminous surfacing.

Step-by-Step Reasoning:

Verification / Alternative check:

Other pioneers: Tresaguet focused on stone-paved roads with dressed stones; Telford advanced foundation layers with large stones and set stringent drainage practices. Macadam’s layered small-stone approach became the hallmark of early modern roads.

Why Other Options Are Wrong:

• Sully, Tresaguet, Telford, Metcalf: Important contributors, but “macadamized” system is specifically credited to Macadam.

Common Pitfalls:

• Confusing Telford’s large stone foundations with Macadam’s smaller, uniform aggregate layers.

Final Answer:

Macadam.