Capacity standards: what are the typical capacities for (i) a one-way 1.5 m wide sidewalk (persons per hour) and (ii) a one-way 2-lane urban road with no frontage access, no standing vehicles, and very little cross traffic (PCU per hour)?

Introduction / Context:
Planning and traffic engineering rely on benchmark capacities to size facilities. For pedestrian sidewalks and multi-lane urban roads, conventional design manuals provide typical one-way capacities under specified assumptions (unobstructed flow, good surface, limited conflicts). This question tests recall of standard order-of-magnitude values used for preliminary design checks.

Given Data / Assumptions:

• Sidewalk width = 1.5 m, one-way pedestrian movement.
• Urban road: 2 lanes in one direction, minimal frontage access, no standing vehicles, very low cross traffic.
• Capacities expressed as persons per hour (sidewalk) and PCU per hour (road).

Concept / Approach:
Pedestrian facility capacity depends on flow density, desired speed, and comfort level; a 1.5 m one-way sidewalk commonly carries about 1200 persons/hour comfortably. A one-way 2-lane urban road without side frictions typically carries about 2400 PCU/hour (≈1200 PCU per lane) under good conditions.

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