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FA-67956 / Traffic signal timing plans / Open access

Pedestrian walk and clearance timing: no credit is taken for FDW overlapping the yellow and all-red · case 01

Pedestrian walk and clearance timing returns a wrong result when no credit is taken for FDW overlapping the yellow and all-red.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The vehicle green is sized to contain the whole pedestrian interval although FDW may run through the change interval.

THE FAILURE

The vehicle green is sized to contain the whole pedestrian interval although FDW may run through the change interval.

Unsuccessful approach: Crediting only the yellow still ignores the all-red portion of the permitted overlap.

Case contract

Input {crossing_ft, walk_speed_tenths (ft/s*10), min_walk, yellow_tenths, red_tenths, min_green, ped_call, split}. FDW = ceil(crossing*10/speed). Walk starts at min_walk and is extended so that walk + FDW >= ceil((crossing + 6)/3.0) (pushbutton-to-far-curb check at 3.0 ft/s). FDW may overlap yellow and all-red, so with a ped call the vehicle green is max(min_green, ceil(walk + FDW - (yellow+red))). Without a call green = min_green. fits is green + yellow + red <= split. Return {walk, fdw, green, fits}.

Why this case matters

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

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
import math
N = 1
observations = []
def solve(x):
    sp = x['walk_speed_tenths']
    fdw = -(-x['crossing_ft'] * 10 // sp)
    walk = x['min_walk']
    total = -(-(x['crossing_ft'] + 6) * 10 // 30)
    if walk + fdw < total:
        walk = total - fdw
    yr = Fraction(x['yellow_tenths'] + x['red_tenths'], 10)
    g = x['min_green']
    if x['ped_call']:
        need = walk + fdw
        g = max(g, math.ceil(need))
    return {'walk': walk, 'fdw': fdw, 'green': g, 'fits': g + yr <= x['split']}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 25, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 30, 'red_tenths': 20, 'min_green': 8, 'ped_call': False, 'split': 18}, {'walk': 4, 'fdw': 7, 'green': 8, 'fits': True}), ({'crossing_ft': 50, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 10, 'ped_call': False, 'split': 21}, {'walk': 4, 'fdw': 15, 'green': 10, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 51, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 5, 'ped_call': True, 'split': 22}, {'walk': 10, 'fdw': 15, 'green': 21, 'fits': False}), ({'crossing_ft': 40, 'walk_speed_tenths': 30, 'min_walk': 10, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 23}, {'walk': 10, 'fdw': 14, 'green': 18, 'fits': False}), ({'crossing_ft': 103, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 5, 'ped_call': False, 'split': 31}, {'walk': 10, 'fdw': 30, 'green': 5, 'fits': True})], [({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 91, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 8, 'ped_call': False, 'split': 42}, {'walk': 7, 'fdw': 26, 'green': 8, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 91, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 15, 'ped_call': False, 'split': 37}, {'walk': 7, 'fdw': 26, 'green': 15, 'fits': True}), ({'crossing_ft': 85, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 10, 'min_green': 10, 'ped_call': False, 'split': 18}, {'walk': 10, 'fdw': 25, 'green': 10, 'fits': True}), ({'crossing_ft': 62, 'walk_speed_tenths': 40, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 8, 'ped_call': True, 'split': 27}, {'walk': 10, 'fdw': 16, 'green': 21, 'fits': True}), ({'crossing_ft': 30, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 10, 'ped_call': False, 'split': 17}, {'walk': 7, 'fdw': 9, 'green': 10, 'fits': True})], [({'crossing_ft': 35, 'walk_speed_tenths': 30, 'min_walk': 5, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 8, 'ped_call': False, 'split': 27}, {'walk': 5, 'fdw': 12, 'green': 8, 'fits': True}), ({'crossing_ft': 30, 'walk_speed_tenths': 30, 'min_walk': 4, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 15, 'ped_call': True, 'split': 39}, {'walk': 4, 'fdw': 10, 'green': 15, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 104, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': True, 'split': 36}, {'walk': 7, 'fdw': 30, 'green': 32, 'fits': False}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 96, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': False, 'split': 37}, {'walk': 6, 'fdw': 28, 'green': 5, 'fits': True}), ({'crossing_ft': 68, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 45, 'red_tenths': 10, 'min_green': 15, 'ped_call': True, 'split': 38}, {'walk': 8, 'fdw': 17, 'green': 20, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True})], [({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 44, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 15, 'min_green': 5, 'ped_call': False, 'split': 40}, {'walk': 7, 'fdw': 13, 'green': 5, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 46, 'walk_speed_tenths': 30, 'min_walk': 10, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 8, 'ped_call': False, 'split': 43}, {'walk': 10, 'fdw': 16, 'green': 8, 'fits': True}), ({'crossing_ft': 35, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 20, 'min_green': 8, 'ped_call': True, 'split': 42}, {'walk': 7, 'fdw': 10, 'green': 11, 'fits': True}), ({'crossing_ft': 43, 'walk_speed_tenths': 30, 'min_walk': 5, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 10, 'ped_call': False, 'split': 32}, {'walk': 5, 'fdw': 15, 'green': 10, 'fits': True}), ({'crossing_ft': 107, 'walk_speed_tenths': 40, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 10, 'ped_call': False, 'split': 19}, {'walk': 11, 'fdw': 27, 'green': 10, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True})], [({'crossing_ft': 29, 'walk_speed_tenths': 30, 'min_walk': 10, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 15, 'ped_call': True, 'split': 29}, {'walk': 10, 'fdw': 10, 'green': 16, 'fits': True}), ({'crossing_ft': 48, 'walk_speed_tenths': 30, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 5, 'ped_call': False, 'split': 44}, {'walk': 10, 'fdw': 16, 'green': 5, 'fits': True}), ({'crossing_ft': 108, 'walk_speed_tenths': 30, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 10, 'min_green': 10, 'ped_call': True, 'split': 26}, {'walk': 4, 'fdw': 36, 'green': 36, 'fits': False}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 74, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 10, 'ped_call': False, 'split': 42}, {'walk': 8, 'fdw': 19, 'green': 10, 'fits': True}), ({'crossing_ft': 101, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 35, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 23}, {'walk': 7, 'fdw': 29, 'green': 8, 'fits': True})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('timing oracle' + ' %d' % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
timing oracle 0{'fdw': 20, 'fits': False, 'green': 27, 'walk': 7}{'fdw': 20, 'fits': True, 'green': 21, 'walk': 7}Failed
timing oracle 1{'fdw': 26, 'fits': False, 'green': 32, 'walk': 6}{'fdw': 26, 'fits': True, 'green': 27, 'walk': 6}Failed
timing oracle 2{'fdw': 7, 'fits': True, 'green': 8, 'walk': 4}{'fdw': 7, 'fits': True, 'green': 8, 'walk': 4}Passed
timing oracle 3{'fdw': 15, 'fits': True, 'green': 10, 'walk': 4}{'fdw': 15, 'fits': True, 'green': 10, 'walk': 4}Passed
timing oracle 4{'fdw': 9, 'fits': True, 'green': 8, 'walk': 7}{'fdw': 9, 'fits': True, 'green': 8, 'walk': 7}Passed
timing oracle 5{'fdw': 15, 'fits': False, 'green': 25, 'walk': 10}{'fdw': 15, 'fits': False, 'green': 21, 'walk': 10}Failed
timing oracle 6{'fdw': 14, 'fits': False, 'green': 24, 'walk': 10}{'fdw': 14, 'fits': False, 'green': 18, 'walk': 10}Failed
timing oracle 7{'fdw': 30, 'fits': True, 'green': 5, 'walk': 10}{'fdw': 30, 'fits': True, 'green': 5, 'walk': 10}Passed

SHA-256 / 3c5933b5a3f43082de2e3387a49c58e4beb1722e641092438c2810c83c96181b

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
import math
N = 1
observations = []
def solve(x):
    sp = x['walk_speed_tenths']
    fdw = -(-x['crossing_ft'] * 10 // sp)
    walk = x['min_walk']
    total = -(-(x['crossing_ft'] + 6) * 10 // 30)
    if walk + fdw < total:
        walk = total - fdw
    yr = Fraction(x['yellow_tenths'] + x['red_tenths'], 10)
    g = x['min_green']
    if x['ped_call']:
        need = walk + fdw - Fraction(x['yellow_tenths'], 10)
        g = max(g, math.ceil(need))
    return {'walk': walk, 'fdw': fdw, 'green': g, 'fits': g + yr <= x['split']}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 25, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 30, 'red_tenths': 20, 'min_green': 8, 'ped_call': False, 'split': 18}, {'walk': 4, 'fdw': 7, 'green': 8, 'fits': True}), ({'crossing_ft': 50, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 10, 'ped_call': False, 'split': 21}, {'walk': 4, 'fdw': 15, 'green': 10, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 51, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 5, 'ped_call': True, 'split': 22}, {'walk': 10, 'fdw': 15, 'green': 21, 'fits': False}), ({'crossing_ft': 40, 'walk_speed_tenths': 30, 'min_walk': 10, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 23}, {'walk': 10, 'fdw': 14, 'green': 18, 'fits': False}), ({'crossing_ft': 103, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 5, 'ped_call': False, 'split': 31}, {'walk': 10, 'fdw': 30, 'green': 5, 'fits': True})], [({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 91, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 8, 'ped_call': False, 'split': 42}, {'walk': 7, 'fdw': 26, 'green': 8, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 91, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 15, 'ped_call': False, 'split': 37}, {'walk': 7, 'fdw': 26, 'green': 15, 'fits': True}), ({'crossing_ft': 85, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 10, 'min_green': 10, 'ped_call': False, 'split': 18}, {'walk': 10, 'fdw': 25, 'green': 10, 'fits': True}), ({'crossing_ft': 62, 'walk_speed_tenths': 40, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 8, 'ped_call': True, 'split': 27}, {'walk': 10, 'fdw': 16, 'green': 21, 'fits': True}), ({'crossing_ft': 30, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 10, 'ped_call': False, 'split': 17}, {'walk': 7, 'fdw': 9, 'green': 10, 'fits': True})], [({'crossing_ft': 35, 'walk_speed_tenths': 30, 'min_walk': 5, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 8, 'ped_call': False, 'split': 27}, {'walk': 5, 'fdw': 12, 'green': 8, 'fits': True}), ({'crossing_ft': 30, 'walk_speed_tenths': 30, 'min_walk': 4, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 15, 'ped_call': True, 'split': 39}, {'walk': 4, 'fdw': 10, 'green': 15, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 104, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': True, 'split': 36}, {'walk': 7, 'fdw': 30, 'green': 32, 'fits': False}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 96, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': False, 'split': 37}, {'walk': 6, 'fdw': 28, 'green': 5, 'fits': True}), ({'crossing_ft': 68, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 45, 'red_tenths': 10, 'min_green': 15, 'ped_call': True, 'split': 38}, {'walk': 8, 'fdw': 17, 'green': 20, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True})], [({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 44, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 15, 'min_green': 5, 'ped_call': False, 'split': 40}, {'walk': 7, 'fdw': 13, 'green': 5, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 46, 'walk_speed_tenths': 30, 'min_walk': 10, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 8, 'ped_call': False, 'split': 43}, {'walk': 10, 'fdw': 16, 'green': 8, 'fits': True}), ({'crossing_ft': 35, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 20, 'min_green': 8, 'ped_call': True, 'split': 42}, {'walk': 7, 'fdw': 10, 'green': 11, 'fits': True}), ({'crossing_ft': 43, 'walk_speed_tenths': 30, 'min_walk': 5, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 10, 'ped_call': False, 'split': 32}, {'walk': 5, 'fdw': 15, 'green': 10, 'fits': True}), ({'crossing_ft': 107, 'walk_speed_tenths': 40, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 10, 'ped_call': False, 'split': 19}, {'walk': 11, 'fdw': 27, 'green': 10, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True})], [({'crossing_ft': 29, 'walk_speed_tenths': 30, 'min_walk': 10, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 15, 'ped_call': True, 'split': 29}, {'walk': 10, 'fdw': 10, 'green': 16, 'fits': True}), ({'crossing_ft': 48, 'walk_speed_tenths': 30, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 5, 'ped_call': False, 'split': 44}, {'walk': 10, 'fdw': 16, 'green': 5, 'fits': True}), ({'crossing_ft': 108, 'walk_speed_tenths': 30, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 10, 'min_green': 10, 'ped_call': True, 'split': 26}, {'walk': 4, 'fdw': 36, 'green': 36, 'fits': False}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 74, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 30, 'red_tenths': 15, 'min_green': 10, 'ped_call': False, 'split': 42}, {'walk': 8, 'fdw': 19, 'green': 10, 'fits': True}), ({'crossing_ft': 101, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 35, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 23}, {'walk': 7, 'fdw': 29, 'green': 8, 'fits': True})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('timing oracle' + ' %d' % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
timing oracle 0{'fdw': 20, 'fits': True, 'green': 23, 'walk': 7}{'fdw': 20, 'fits': True, 'green': 21, 'walk': 7}Failed
timing oracle 1{'fdw': 26, 'fits': True, 'green': 29, 'walk': 6}{'fdw': 26, 'fits': True, 'green': 27, 'walk': 6}Failed
timing oracle 2{'fdw': 7, 'fits': True, 'green': 8, 'walk': 4}{'fdw': 7, 'fits': True, 'green': 8, 'walk': 4}Passed
timing oracle 3{'fdw': 15, 'fits': True, 'green': 10, 'walk': 4}{'fdw': 15, 'fits': True, 'green': 10, 'walk': 4}Passed
timing oracle 4{'fdw': 9, 'fits': True, 'green': 8, 'walk': 7}{'fdw': 9, 'fits': True, 'green': 8, 'walk': 7}Passed
timing oracle 5{'fdw': 15, 'fits': False, 'green': 22, 'walk': 10}{'fdw': 15, 'fits': False, 'green': 21, 'walk': 10}Failed
timing oracle 6{'fdw': 14, 'fits': False, 'green': 20, 'walk': 10}{'fdw': 14, 'fits': False, 'green': 18, 'walk': 10}Failed
timing oracle 7{'fdw': 30, 'fits': True, 'green': 5, 'walk': 10}{'fdw': 30, 'fits': True, 'green': 5, 'walk': 10}Passed

SHA-256 / 1f00d646a2c32a7175a4efa53a20994bfa1b37c3e97272c15b8a4996cbd3894d

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

A deterministic, bounded toy model with a stipulated contract; it makes no claim of conformance to any agency manual or standard. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:47:57.722838+00:00.

Case digest / 2e720a3e86b4afe39021f27fe4b57cf12859b608ae3c1c2c13db165b43b33f96