Pedestrian Level of Service Calculator

This calculator reserves 1.5 feet along the building face and 1.5 feet along the curb as a standing buffer pedestrians naturally avoid walking directly against -- shy distance from walls, storefronts, and the traffic edge. That fixed 3-foot deduction applies before obstructions like signs or poles are subtracted, so even a completely clear sidewalk never counts its full nominal width as usable walking space.

It depends on the sidewalk's starting width and pedestrian volume, since each obstruction only subtracts about 1 foot of effective width in this calculator's model, and LOS grade responds to the flow-rate ratio (pedestrians per minute over effective width), not obstruction count directly. On a narrower sidewalk already close to a grade boundary, even one or two additional obstructions can meaningfully raise flow rate and drop the LOS letter grade; on a wide, lightly used sidewalk the same obstructions barely move it.

This calculator follows the HCM's six-tier pedestrian LOS scale: LOS A holds at or below 5 pedestrians per minute per foot of effective width (free, comfortable walking), while LOS F is anything above 23 pedestrians per minute per foot, where crowding significantly restricts walking speed and the ability to pass other pedestrians. The letters B through E mark intermediate flow-rate thresholds between those two extremes (B up to 7, C up to 10, D up to 15, E up to 23).

Wider sidewalks do lower flow rate (and improve LOS) for a given pedestrian volume and obstruction count, since flow rate is peak pedestrians per minute divided by effective width -- but the relationship isn't perfectly linear against nominal width, because the fixed 3-foot edge buffer and any per-obstruction deductions are subtracted first. A very narrow sidewalk loses a larger share of its width to that fixed buffer than a wide one does, so incremental width tends to help a narrow, congested sidewalk more than it helps an already-wide one.