FAILURE MAP
← Case archive

FA-67926 / Traffic signal timing plans / Open access

Yellow and all-red intervals: the far crosswalk is added when no pedestrians are present · case 01

Yellow and all-red intervals returns a wrong result when the far crosswalk is added when no pedestrians are present.

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

ROOT CAUSE

The pedestrian flag is inverted, so the clearance distance includes the crosswalk exactly when it should not.

VERIFIED REPAIR

Restore the far crosswalk width rule so that the step reads `(x['crosswalk_ft'] if x['ped'] else 0)`.

Unsuccessful approach: Adding half the crosswalk still under-clears the far crosswalk when pedestrians are present.

Case contract

Input {speed_mph, grade_pct (uphill positive), reaction_tenths, decel ft/s^2, width_ft, veh_len_ft, crosswalk_ft, ped}. v = 1.467*speed ft/s; yellow = t + v/(2a + 2*32.2*grade/100), rounded UP to 0.1 s and clamped to [3.0, 6.0]; a non-positive denominator returns 'invalid'. All-red = (W + vehicle length)/v where W includes the far crosswalk when ped is true, rounded UP to 0.1 s and clamped to [1.0, 6.0]. Return tenths.

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):
    v = Fraction(x['speed_mph']) * Fraction(1467, 1000)
    t = Fraction(x['reaction_tenths'], 10)
    den = 2 * x['decel'] + 2 * Fraction(322, 10) * Fraction(x['grade_pct'], 100)
    if den <= 0:
        return 'invalid'
    yl = max(30, min(60, math.ceil((t + v / den) * 10)))
    w = x['width_ft'] + (x['crosswalk_ft'] if not x['ped'] else 0)
    rd = max(10, min(60, math.ceil((w + x['veh_len_ft']) / v * 10)))
    return {'yellow_tenths': yl, 'red_tenths': rd}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 70, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 55, 'grade_pct': 4, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 93, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 44, 'red_tenths': 16}), ({'speed_mph': 65, 'grade_pct': 3, 'reaction_tenths': 8, 'decel': 12, 'width_ft': 61, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 45, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': 4, 'reaction_tenths': 10, 'decel': 11, 'width_ft': 62, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 49, 'red_tenths': 10})], [({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 25, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 50, 'grade_pct': 0, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 70, 'veh_len_ft': 40, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 45, 'red_tenths': 17}), ({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 41, 'veh_len_ft': 16, 'crosswalk_ft': 8, 'ped': True}, {'yellow_tenths': 53, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': 3, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 57, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 57, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 70, 'grade_pct': 4, 'reaction_tenths': 12, 'decel': 10, 'width_ft': 54, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 58, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19})], [({'speed_mph': 30, 'grade_pct': 5, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 25, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 30, 'red_tenths': 20}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 60, 'grade_pct': -6, 'reaction_tenths': 10, 'decel': 8, 'width_ft': 40, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': -6, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 55, 'veh_len_ft': 25, 'crosswalk_ft': 15, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': 7, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 56, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 47, 'red_tenths': 10}), ({'speed_mph': 70, 'grade_pct': 4, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 44, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 54, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16})], [({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 8, 'decel': 8, 'width_ft': 124, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 50, 'grade_pct': 6, 'reaction_tenths': 12, 'decel': 11, 'width_ft': 40, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 41, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 20, 'grade_pct': -2, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 114, 'veh_len_ft': 25, 'crosswalk_ft': 8, 'ped': True}, {'yellow_tenths': 31, 'red_tenths': 51}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 20, 'grade_pct': 6, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 135, 'veh_len_ft': 40, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 30, 'red_tenths': 60}), ({'speed_mph': 60, 'grade_pct': -4, 'reaction_tenths': 12, 'decel': 10, 'width_ft': 57, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10})], [({'speed_mph': 65, 'grade_pct': 6, 'reaction_tenths': 8, 'decel': 12, 'width_ft': 80, 'veh_len_ft': 25, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 43, 'red_tenths': 12}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 12, 'width_ft': 69, 'veh_len_ft': 16, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 58, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': -6, 'reaction_tenths': 10, 'decel': 11, 'width_ft': 66, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 35, 'red_tenths': 23}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 70, 'grade_pct': 6, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 46, 'veh_len_ft': 16, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 59, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 8, 'width_ft': 48, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10})]]
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{'red_tenths': 16, 'yellow_tenths': 48}{'red_tenths': 17, 'yellow_tenths': 48}Failed
timing oracle 1{'red_tenths': 10, 'yellow_tenths': 60}{'red_tenths': 10, 'yellow_tenths': 60}Passed
timing oracle 2{'red_tenths': 15, 'yellow_tenths': 44}{'red_tenths': 16, 'yellow_tenths': 44}Failed
timing oracle 3{'red_tenths': 10, 'yellow_tenths': 45}{'red_tenths': 10, 'yellow_tenths': 45}Passed
timing oracle 4{'red_tenths': 10, 'yellow_tenths': 60}{'red_tenths': 10, 'yellow_tenths': 60}Passed
timing oracle 5{'red_tenths': 15, 'yellow_tenths': 60}{'red_tenths': 16, 'yellow_tenths': 60}Failed
timing oracle 6{'red_tenths': 21, 'yellow_tenths': 33}{'red_tenths': 19, 'yellow_tenths': 33}Failed
timing oracle 7{'red_tenths': 10, 'yellow_tenths': 49}{'red_tenths': 10, 'yellow_tenths': 49}Passed

SHA-256 / c7627ebd452c129268bc0d65589cb5e26e7a6179c68c51e2d1fa5602fa2ef16e

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):
    v = Fraction(x['speed_mph']) * Fraction(1467, 1000)
    t = Fraction(x['reaction_tenths'], 10)
    den = 2 * x['decel'] + 2 * Fraction(322, 10) * Fraction(x['grade_pct'], 100)
    if den <= 0:
        return 'invalid'
    yl = max(30, min(60, math.ceil((t + v / den) * 10)))
    w = x['width_ft'] + (x['crosswalk_ft'] // 2 if x['ped'] else 0)
    rd = max(10, min(60, math.ceil((w + x['veh_len_ft']) / v * 10)))
    return {'yellow_tenths': yl, 'red_tenths': rd}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 70, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 55, 'grade_pct': 4, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 93, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 44, 'red_tenths': 16}), ({'speed_mph': 65, 'grade_pct': 3, 'reaction_tenths': 8, 'decel': 12, 'width_ft': 61, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 45, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': 4, 'reaction_tenths': 10, 'decel': 11, 'width_ft': 62, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 49, 'red_tenths': 10})], [({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 25, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 50, 'grade_pct': 0, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 70, 'veh_len_ft': 40, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 45, 'red_tenths': 17}), ({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 41, 'veh_len_ft': 16, 'crosswalk_ft': 8, 'ped': True}, {'yellow_tenths': 53, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': 3, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 57, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 57, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 70, 'grade_pct': 4, 'reaction_tenths': 12, 'decel': 10, 'width_ft': 54, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 58, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19})], [({'speed_mph': 30, 'grade_pct': 5, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 25, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 30, 'red_tenths': 20}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 60, 'grade_pct': -6, 'reaction_tenths': 10, 'decel': 8, 'width_ft': 40, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': -6, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 55, 'veh_len_ft': 25, 'crosswalk_ft': 15, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': 7, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 56, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 47, 'red_tenths': 10}), ({'speed_mph': 70, 'grade_pct': 4, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 44, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 54, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16})], [({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 8, 'decel': 8, 'width_ft': 124, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 50, 'grade_pct': 6, 'reaction_tenths': 12, 'decel': 11, 'width_ft': 40, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 41, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 20, 'grade_pct': -2, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 114, 'veh_len_ft': 25, 'crosswalk_ft': 8, 'ped': True}, {'yellow_tenths': 31, 'red_tenths': 51}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 20, 'grade_pct': 6, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 135, 'veh_len_ft': 40, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 30, 'red_tenths': 60}), ({'speed_mph': 60, 'grade_pct': -4, 'reaction_tenths': 12, 'decel': 10, 'width_ft': 57, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10})], [({'speed_mph': 65, 'grade_pct': 6, 'reaction_tenths': 8, 'decel': 12, 'width_ft': 80, 'veh_len_ft': 25, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 43, 'red_tenths': 12}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 12, 'width_ft': 69, 'veh_len_ft': 16, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 58, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': -6, 'reaction_tenths': 10, 'decel': 11, 'width_ft': 66, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 35, 'red_tenths': 23}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 70, 'grade_pct': 6, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 46, 'veh_len_ft': 16, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 59, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 8, 'width_ft': 48, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10})]]
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{'red_tenths': 16, 'yellow_tenths': 48}{'red_tenths': 17, 'yellow_tenths': 48}Failed
timing oracle 1{'red_tenths': 10, 'yellow_tenths': 60}{'red_tenths': 10, 'yellow_tenths': 60}Passed
timing oracle 2{'red_tenths': 15, 'yellow_tenths': 44}{'red_tenths': 16, 'yellow_tenths': 44}Failed
timing oracle 3{'red_tenths': 10, 'yellow_tenths': 45}{'red_tenths': 10, 'yellow_tenths': 45}Passed
timing oracle 4{'red_tenths': 10, 'yellow_tenths': 60}{'red_tenths': 10, 'yellow_tenths': 60}Passed
timing oracle 5{'red_tenths': 16, 'yellow_tenths': 60}{'red_tenths': 16, 'yellow_tenths': 60}Passed
timing oracle 6{'red_tenths': 19, 'yellow_tenths': 33}{'red_tenths': 19, 'yellow_tenths': 33}Passed
timing oracle 7{'red_tenths': 10, 'yellow_tenths': 49}{'red_tenths': 10, 'yellow_tenths': 49}Passed

SHA-256 / b18f00a545cd738a85ee9f088dddfd1c30bff177130a757f3aea3f4ff158ccc7

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
import math
N = 1
observations = []
def solve(x):
    v = Fraction(x['speed_mph']) * Fraction(1467, 1000)
    t = Fraction(x['reaction_tenths'], 10)
    den = 2 * x['decel'] + 2 * Fraction(322, 10) * Fraction(x['grade_pct'], 100)
    if den <= 0:
        return 'invalid'
    yl = max(30, min(60, math.ceil((t + v / den) * 10)))
    w = x['width_ft'] + (x['crosswalk_ft'] if x['ped'] else 0)
    rd = max(10, min(60, math.ceil((w + x['veh_len_ft']) / v * 10)))
    return {'yellow_tenths': yl, 'red_tenths': rd}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 70, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 55, 'grade_pct': 4, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 93, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 44, 'red_tenths': 16}), ({'speed_mph': 65, 'grade_pct': 3, 'reaction_tenths': 8, 'decel': 12, 'width_ft': 61, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 45, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': 4, 'reaction_tenths': 10, 'decel': 11, 'width_ft': 62, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 49, 'red_tenths': 10})], [({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 25, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 50, 'grade_pct': 0, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 70, 'veh_len_ft': 40, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 45, 'red_tenths': 17}), ({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 41, 'veh_len_ft': 16, 'crosswalk_ft': 8, 'ped': True}, {'yellow_tenths': 53, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': 3, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 57, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 57, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 70, 'grade_pct': 4, 'reaction_tenths': 12, 'decel': 10, 'width_ft': 54, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 58, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19})], [({'speed_mph': 30, 'grade_pct': 5, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 47, 'veh_len_ft': 25, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 30, 'red_tenths': 20}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 60, 'grade_pct': -6, 'reaction_tenths': 10, 'decel': 8, 'width_ft': 40, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': -6, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 55, 'veh_len_ft': 25, 'crosswalk_ft': 15, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': 7, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 56, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': False}, {'yellow_tenths': 47, 'red_tenths': 10}), ({'speed_mph': 70, 'grade_pct': 4, 'reaction_tenths': 8, 'decel': 10, 'width_ft': 44, 'veh_len_ft': 20, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 54, 'red_tenths': 10}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16})], [({'speed_mph': 65, 'grade_pct': 2, 'reaction_tenths': 8, 'decel': 8, 'width_ft': 124, 'veh_len_ft': 20, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 50, 'grade_pct': 6, 'reaction_tenths': 12, 'decel': 11, 'width_ft': 40, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 41, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 20, 'grade_pct': -2, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 114, 'veh_len_ft': 25, 'crosswalk_ft': 8, 'ped': True}, {'yellow_tenths': 31, 'red_tenths': 51}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 20, 'grade_pct': 6, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 135, 'veh_len_ft': 40, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 30, 'red_tenths': 60}), ({'speed_mph': 60, 'grade_pct': -4, 'reaction_tenths': 12, 'decel': 10, 'width_ft': 57, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10})], [({'speed_mph': 65, 'grade_pct': 6, 'reaction_tenths': 8, 'decel': 12, 'width_ft': 80, 'veh_len_ft': 25, 'crosswalk_ft': 8, 'ped': False}, {'yellow_tenths': 43, 'red_tenths': 12}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 12, 'width_ft': 69, 'veh_len_ft': 16, 'crosswalk_ft': 15, 'ped': True}, {'yellow_tenths': 58, 'red_tenths': 10}), ({'speed_mph': 30, 'grade_pct': -6, 'reaction_tenths': 10, 'decel': 11, 'width_ft': 66, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 35, 'red_tenths': 23}), ({'speed_mph': 65, 'grade_pct': -7, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 120, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 16}), ({'speed_mph': 30, 'grade_pct': 0, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 60, 'veh_len_ft': 20, 'crosswalk_ft': 12, 'ped': False}, {'yellow_tenths': 33, 'red_tenths': 19}), ({'speed_mph': 70, 'grade_pct': 6, 'reaction_tenths': 15, 'decel': 10, 'width_ft': 46, 'veh_len_ft': 16, 'crosswalk_ft': 12, 'ped': True}, {'yellow_tenths': 59, 'red_tenths': 10}), ({'speed_mph': 45, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 10, 'width_ft': 80, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 48, 'red_tenths': 17}), ({'speed_mph': 70, 'grade_pct': -4, 'reaction_tenths': 10, 'decel': 8, 'width_ft': 48, 'veh_len_ft': 20, 'crosswalk_ft': 10, 'ped': True}, {'yellow_tenths': 60, 'red_tenths': 10})]]
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{'red_tenths': 17, 'yellow_tenths': 48}{'red_tenths': 17, 'yellow_tenths': 48}Passed
timing oracle 1{'red_tenths': 10, 'yellow_tenths': 60}{'red_tenths': 10, 'yellow_tenths': 60}Passed
timing oracle 2{'red_tenths': 16, 'yellow_tenths': 44}{'red_tenths': 16, 'yellow_tenths': 44}Passed
timing oracle 3{'red_tenths': 10, 'yellow_tenths': 45}{'red_tenths': 10, 'yellow_tenths': 45}Passed
timing oracle 4{'red_tenths': 10, 'yellow_tenths': 60}{'red_tenths': 10, 'yellow_tenths': 60}Passed
timing oracle 5{'red_tenths': 16, 'yellow_tenths': 60}{'red_tenths': 16, 'yellow_tenths': 60}Passed
timing oracle 6{'red_tenths': 19, 'yellow_tenths': 33}{'red_tenths': 19, 'yellow_tenths': 33}Passed
timing oracle 7{'red_tenths': 10, 'yellow_tenths': 49}{'red_tenths': 10, 'yellow_tenths': 49}Passed

SHA-256 / 12db4543688c47c8526f0df77a2b79f06315521bbe0d76bac3bfd29483a94b2a

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 2026-09-29T14:47:57.413865+00:00.

Case digest / 589113fa93df5ef2cb8dd3c83190fb29f48d561ff43802ac4dd848e01929a4ff