FA-68223 / Traffic signal timing plans / Member archive

Transit signal priority decision: early green always uses the maximum advance · case 03

Transit signal priority decision returns a wrong result when early green always uses the maximum advance.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Input {cycle, green_start, green_end (exclusive), max_ext, max_early, arrival (seconds, reduced modulo cycle), last_granted (cycle index or null), cycle_index, lockout}. A request within lockout cycles of the last grant (difference <= lockout) returns ['locked', 0]. Arrival in green needs nothing. If the arrival is less than max_ext seconds after green end (cyclically) green is extended through the arrival second: ['extend', d+1]. Otherwise green starts early by min(max_early, seconds until next green start).

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 0	`["early", 24]`	`["early", 10]`	Failed

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