Standard lane width for a single lane road without kerbs is $3.5\text{ m}$.

Raised kerbs necessitate an additional offset of $0.25\text{ m}$ per lane.

The total width of $3.75\text{ m}$ is specifically for the carriageway, excluding kerb width and shoulder.

For two-lane roads with raised kerbs, the width is increased by $0.25\text{ m}$ on each side, totaling $7.5\text{ m}$.

Prevents vehicles from encroaching onto the shoulder.

Provides clear delineation between the carriageway and pedestrian facilities.

Improves safety in constrained urban or semi-urban environments.

Increased cost of construction due to kerb installation.

May lead to increased vehicle damage if kerbs are struck at high speeds.

Urban roads with restricted right-of-way.

Approach roads to bridges and culverts where pedestrian safety is required.

Road sections with heavy pedestrian traffic.

The standard width for a single lane carriageway on a normal road (without kerbs) is $3.5\text{ m}$.

Option A ($3\text{ m}$) is too narrow for standard traffic, Option C ($2.5\text{ m}$) is below design standards for public highways, and Option D ($2\text{ m}$) is generally used only for cycle tracks or very narrow rural pathways.