Vehicle operation – typical rolling resistance on smooth hard-surfaced roads On most smooth, hard-surfaced roads, the rolling resistance experienced by vehicles commonly ranges between:

Introduction / Context:
Rolling resistance is the tractive effort needed to overcome tire and surface losses at constant speed on level ground. It is a key input to gradeability, fuel use, and capacity calculations.

Given Data / Assumptions:

• Smooth, hard-surfaced pavement (e.g., well-maintained bituminous or concrete).
• Moderate speeds with properly inflated tires.
• Resistance expressed as an equivalent force per tonne of vehicle weight.

Concept / Approach:
Empirical ranges show that on good pavements the rolling resistance is low, typically a few kilograms per tonne. Rougher pavements and poor tires increase this value substantially.

Step-by-Step Solution:

Verification / Alternative check:
Textbook tables of road resistances list ≈ 5–7 kg/tonne for first-class pavements, increasing with surface roughness or poor maintenance.

Why Other Options Are Wrong:
Higher bands correspond to rough macadam, gravel, or broken surfaces; they do not match the “most smooth hard” case.

Common Pitfalls:
Using fixed resistance irrespective of speed, tire pressure, or grade; ignoring wind and mechanical losses which are separate.

Final Answer:
5 kg to 7 kg per tonne of vehicle weight