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FA-67386 / Elevator dispatch scheduling / Open access

Door dwell time calculation: stop type base · case 01

A stop serving both hall and car calls closes its doors too quickly.

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

ROOT CAUSE

Only pure hall-call stops get the hall-call base time.

THE FAILURE

Only pure hall-call stops get the hall-call base time.

Unsuccessful approach: Averaging the two bases for mixed stops still shortens the hall-call dwell.

Case contract

Dwell time in deciseconds: base 40 for a hall call stop (or a stop with both hall and car calls), 25 for a car-call-only stop. Accessible mode extends the base by half (integer). Every passenger beyond the first adds 10. The result is capped at 150. From the third reopen onward the door nudges with a fixed dwell of 20.

Why this case matters

Lift group controllers make these decisions many times per minute; a wrong answer strands passengers, wastes trips or overrides a safety rule.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    base = 40 if x['call_type'] == 'hall' else 25
    if x['accessible']:
        base = base * 3 // 2
    pax = x['boarding'] + x['alighting']
    dwell = base + 10 * max(pax - 1, 0)
    dwell = min(dwell, 150)
    nudge = x['reopen_count'] >= 3
    if nudge:
        dwell = 20
    return {'dwell_ds': dwell, 'nudge': nudge}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 19', {'call_type': 'both', 'boarding': 1, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 90, 'nudge': False}), ('sampled regression 3', {'call_type': 'both', 'boarding': 4, 'alighting': 4, 'reopen_count': 2, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('boundary: accessible busy hall stop', {'call_type': 'hall', 'boarding': 5, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('control 1', {'call_type': 'both', 'boarding': 6, 'alighting': 3, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 4', {'call_type': 'hall', 'boarding': 5, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 100, 'nudge': False}), ('control 7', {'call_type': 'both', 'boarding': 5, 'alighting': 1, 'reopen_count': 4, 'accessible': True}, {'dwell_ds': 20, 'nudge': True})], [('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 67', {'call_type': 'both', 'boarding': 6, 'alighting': 1, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 100, 'nudge': False}), ('sampled regression 38', {'call_type': 'both', 'boarding': 5, 'alighting': 3, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 110, 'nudge': False}), ('boundary: accessible busy hall stop', {'call_type': 'hall', 'boarding': 5, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('boundary: nobody boards or alights', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 25, 'nudge': False}), ('control 12', {'call_type': 'car', 'boarding': 0, 'alighting': 4, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 15', {'call_type': 'hall', 'boarding': 2, 'alighting': 5, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 100, 'nudge': False}), ('control 18', {'call_type': 'car', 'boarding': 8, 'alighting': 7, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 150, 'nudge': False})], [('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 19', {'call_type': 'both', 'boarding': 1, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 90, 'nudge': False}), ('sampled regression 77', {'call_type': 'both', 'boarding': 3, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 110, 'nudge': False}), ('boundary: crowd exceeds the cap', {'call_type': 'hall', 'boarding': 8, 'alighting': 8, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 150, 'nudge': False}), ('boundary: third reopen', {'call_type': 'hall', 'boarding': 2, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 23', {'call_type': 'hall', 'boarding': 7, 'alighting': 3, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 130, 'nudge': False}), ('sampled regression 26', {'call_type': 'both', 'boarding': 3, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 110, 'nudge': False}), ('control 29', {'call_type': 'both', 'boarding': 1, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True})], [('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 67', {'call_type': 'both', 'boarding': 6, 'alighting': 1, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 100, 'nudge': False}), ('sampled regression 19', {'call_type': 'both', 'boarding': 1, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 90, 'nudge': False}), ('boundary: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: single passenger', {'call_type': 'hall', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 40, 'nudge': False}), ('control 34', {'call_type': 'hall', 'boarding': 3, 'alighting': 5, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 110, 'nudge': False}), ('control 37', {'call_type': 'hall', 'boarding': 4, 'alighting': 0, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 40', {'call_type': 'car', 'boarding': 1, 'alighting': 8, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True})], [('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 19', {'call_type': 'both', 'boarding': 1, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 90, 'nudge': False}), ('sampled regression 65', {'call_type': 'both', 'boarding': 2, 'alighting': 6, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 110, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('boundary: accessible busy hall stop', {'call_type': 'hall', 'boarding': 5, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('control 45', {'call_type': 'both', 'boarding': 6, 'alighting': 0, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 48', {'call_type': 'hall', 'boarding': 3, 'alighting': 8, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 140, 'nudge': False}), ('control 51', {'call_type': 'hall', 'boarding': 2, 'alighting': 4, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 90, 'nudge': False})]]
for label, args, expected in fixtures[N-1]:
    check(label, 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
regression: stop with hall and car calls{'dwell_ds': 35, 'nudge': False}{'dwell_ds': 50, 'nudge': False}Failed
sampled regression 19{'dwell_ds': 67, 'nudge': False}{'dwell_ds': 90, 'nudge': False}Failed
sampled regression 3{'dwell_ds': 107, 'nudge': False}{'dwell_ds': 130, 'nudge': False}Failed
boundary: accessible car call stop{'dwell_ds': 37, 'nudge': False}{'dwell_ds': 37, 'nudge': False}Passed
boundary: accessible busy hall stop{'dwell_ds': 130, 'nudge': False}{'dwell_ds': 130, 'nudge': False}Passed
control 1{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed
control 4{'dwell_ds': 100, 'nudge': False}{'dwell_ds': 100, 'nudge': False}Passed
control 7{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed

SHA-256 / 76cc1db3e30df4d3a5ce9a8feec3c900c1906a156006f3bd90af2788ed6a74bf

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    base = 40 if x['call_type'] == 'hall' else 25 if x['call_type'] == 'car' else 32
    if x['accessible']:
        base = base * 3 // 2
    pax = x['boarding'] + x['alighting']
    dwell = base + 10 * max(pax - 1, 0)
    dwell = min(dwell, 150)
    nudge = x['reopen_count'] >= 3
    if nudge:
        dwell = 20
    return {'dwell_ds': dwell, 'nudge': nudge}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 19', {'call_type': 'both', 'boarding': 1, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 90, 'nudge': False}), ('sampled regression 3', {'call_type': 'both', 'boarding': 4, 'alighting': 4, 'reopen_count': 2, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('boundary: accessible busy hall stop', {'call_type': 'hall', 'boarding': 5, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('control 1', {'call_type': 'both', 'boarding': 6, 'alighting': 3, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 4', {'call_type': 'hall', 'boarding': 5, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 100, 'nudge': False}), ('control 7', {'call_type': 'both', 'boarding': 5, 'alighting': 1, 'reopen_count': 4, 'accessible': True}, {'dwell_ds': 20, 'nudge': True})], [('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 67', {'call_type': 'both', 'boarding': 6, 'alighting': 1, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 100, 'nudge': False}), ('sampled regression 38', {'call_type': 'both', 'boarding': 5, 'alighting': 3, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 110, 'nudge': False}), ('boundary: accessible busy hall stop', {'call_type': 'hall', 'boarding': 5, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('boundary: nobody boards or alights', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 25, 'nudge': False}), ('control 12', {'call_type': 'car', 'boarding': 0, 'alighting': 4, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 15', {'call_type': 'hall', 'boarding': 2, 'alighting': 5, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 100, 'nudge': False}), ('control 18', {'call_type': 'car', 'boarding': 8, 'alighting': 7, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 150, 'nudge': False})], [('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 19', {'call_type': 'both', 'boarding': 1, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 90, 'nudge': False}), ('sampled regression 77', {'call_type': 'both', 'boarding': 3, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 110, 'nudge': False}), ('boundary: crowd exceeds the cap', {'call_type': 'hall', 'boarding': 8, 'alighting': 8, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 150, 'nudge': False}), ('boundary: third reopen', {'call_type': 'hall', 'boarding': 2, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 23', {'call_type': 'hall', 'boarding': 7, 'alighting': 3, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 130, 'nudge': False}), ('sampled regression 26', {'call_type': 'both', 'boarding': 3, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 110, 'nudge': False}), ('control 29', {'call_type': 'both', 'boarding': 1, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True})], [('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 67', {'call_type': 'both', 'boarding': 6, 'alighting': 1, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 100, 'nudge': False}), ('sampled regression 19', {'call_type': 'both', 'boarding': 1, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 90, 'nudge': False}), ('boundary: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: single passenger', {'call_type': 'hall', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 40, 'nudge': False}), ('control 34', {'call_type': 'hall', 'boarding': 3, 'alighting': 5, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 110, 'nudge': False}), ('control 37', {'call_type': 'hall', 'boarding': 4, 'alighting': 0, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 40', {'call_type': 'car', 'boarding': 1, 'alighting': 8, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True})], [('regression: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('sampled regression 19', {'call_type': 'both', 'boarding': 1, 'alighting': 3, 'reopen_count': 1, 'accessible': True}, {'dwell_ds': 90, 'nudge': False}), ('sampled regression 65', {'call_type': 'both', 'boarding': 2, 'alighting': 6, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 110, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('boundary: accessible busy hall stop', {'call_type': 'hall', 'boarding': 5, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('control 45', {'call_type': 'both', 'boarding': 6, 'alighting': 0, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 48', {'call_type': 'hall', 'boarding': 3, 'alighting': 8, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 140, 'nudge': False}), ('control 51', {'call_type': 'hall', 'boarding': 2, 'alighting': 4, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 90, 'nudge': False})]]
for label, args, expected in fixtures[N-1]:
    check(label, 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
regression: stop with hall and car calls{'dwell_ds': 42, 'nudge': False}{'dwell_ds': 50, 'nudge': False}Failed
sampled regression 19{'dwell_ds': 78, 'nudge': False}{'dwell_ds': 90, 'nudge': False}Failed
sampled regression 3{'dwell_ds': 118, 'nudge': False}{'dwell_ds': 130, 'nudge': False}Failed
boundary: accessible car call stop{'dwell_ds': 37, 'nudge': False}{'dwell_ds': 37, 'nudge': False}Passed
boundary: accessible busy hall stop{'dwell_ds': 130, 'nudge': False}{'dwell_ds': 130, 'nudge': False}Passed
control 1{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed
control 4{'dwell_ds': 100, 'nudge': False}{'dwell_ds': 100, 'nudge': False}Passed
control 7{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed

SHA-256 / c650853da088ab69668901d6ad26d05fd46afd1ca7ffa91e321d12df5a434bc3

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

Stipulated toy lift-control contract for a bounded teaching model; it makes no claim of conformance to any lift code or vendor dispatcher and omits real safety cases. 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 2026-09-29T14:47:52.418061+00:00.

Case digest / 53fcea83a5c8794e27b08207519566f8324e5d5a8d92f19317a38034901c1b88