FA-68138 / Traffic signal timing plans / Member archive

Uniform delay level of service: the delay denominator uses uncapped X · case 03

Uniform delay level of service returns a wrong result when the delay denominator uses uncapped X.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Input {cycle, green, volume, sat_per_lane, lanes}. lam = green/cycle, capacity = sat*lanes*lam, X = volume/capacity, uniform delay d = 0.5*C*(1-lam)^2/(1 - min(1,X)*lam) rounded half up to tenths. LOS thresholds on tenths: <=100 A, <=200 B, <=350 C, <=550 D, <=800 E, else F; any X > 1 is F. Return {vc_milli: floor(1000X), delay_tenths, los}.

Why this case matters

Signal timing arithmetic is exact and integer or rational; a wrong rule silently produces unsafe or inefficient timing plans.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
timing oracle 2	`{"delay_tenths": 523, "los": "F", "vc_milli": 1093}`	`{"delay_tenths": 510, "los": "F", "vc_milli": 1093}`	Failed

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