FA-68181 / Traffic signal timing plans / Open access
Railroad preemption entry timing: pedestrian time and minimum green are added · case 01
Railroad preemption entry timing returns a wrong result when pedestrian time and minimum green are added.
ROOT CAUSE
The pedestrian clearance and remaining preempt minimum run concurrently, so adding them overstates the hold.
VERIFIED REPAIR
Restore the green hold combination rule so that the step reads `max(ped, max(0, x['preempt_min_green'] - el))`.
Unsuccessful approach: Letting any pedestrian time replace the minimum green ignores a longer remaining minimum.
Case contract
Input {state: green|yellow|red (red = all-red clearance), elapsed, min_green, preempt_min_green, yellow, red, fdw, ped: none|walk|fdw, ped_elapsed, ped_truncate, track_current}. If the track clearance phase is already green the answer is [0, 0]. In all-red the remaining red is timed; in yellow the remaining yellow and full red are timed. In green the hold is the larger of the remaining preempt minimum green (not the normal minimum) and the pedestrian time: walk is abandoned and FDW is timed in full, or skipped when ped_truncate; an active FDW completes its remainder unless truncated. Return [seconds until track clearance green, green hold].
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
N = 1
observations = []
def solve(x):
st, el = x['state'], x['elapsed']
y, r, f = x['yellow'], x['red'], x['fdw']
if st == 'green' and x['track_current']:
return [0, 0]
if st == 'red':
return [max(0, r - el), 0]
if st == 'yellow':
return [max(0, y - el) + r, 0]
ped = 0
if x['ped'] == 'walk':
ped = 0 if x['ped_truncate'] else f
elif x['ped'] == 'fdw':
ped = 0 if x['ped_truncate'] else max(0, f - x['ped_elapsed'])
hold = ped + max(0, x['preempt_min_green'] - el)
return [hold + y + r, hold]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 4, 'min_green': 20, 'preempt_min_green': 9, 'yellow': 5, 'red': 2, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 12, 'ped_truncate': False, 'track_current': False}, [12, 5]), ({'state': 'green', 'elapsed': 4, 'min_green': 19, 'preempt_min_green': 5, 'yellow': 3, 'red': 2, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 17, 'ped_truncate': False, 'track_current': False}, [12, 7]), ({'state': 'yellow', 'elapsed': 19, 'min_green': 11, 'preempt_min_green': 3, 'yellow': 5, 'red': 3, 'fdw': 20, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [3, 0]), ({'state': 'green', 'elapsed': 2, 'min_green': 17, 'preempt_min_green': 7, 'yellow': 3, 'red': 1, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [9, 5]), ({'state': 'green', 'elapsed': 2, 'min_green': 9, 'preempt_min_green': 9, 'yellow': 5, 'red': 3, 'fdw': 14, 'ped': 'walk', 'ped_elapsed': 5, 'ped_truncate': False, 'track_current': False}, [22, 14]), ({'state': 'green', 'elapsed': 11, 'min_green': 18, 'preempt_min_green': 8, 'yellow': 5, 'red': 2, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [22, 15])], [({'state': 'yellow', 'elapsed': 17, 'min_green': 10, 'preempt_min_green': 7, 'yellow': 3, 'red': 3, 'fdw': 20, 'ped': 'none', 'ped_elapsed': 2, 'ped_truncate': False, 'track_current': True}, [3, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 0, 'min_green': 10, 'preempt_min_green': 9, 'yellow': 5, 'red': 3, 'fdw': 20, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [17, 9]), ({'state': 'green', 'elapsed': 6, 'min_green': 17, 'preempt_min_green': 7, 'yellow': 5, 'red': 2, 'fdw': 20, 'ped': 'fdw', 'ped_elapsed': 3, 'ped_truncate': False, 'track_current': False}, [24, 17]), ({'state': 'green', 'elapsed': 4, 'min_green': 16, 'preempt_min_green': 8, 'yellow': 5, 'red': 1, 'fdw': 8, 'ped': 'walk', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 7, 'min_green': 19, 'preempt_min_green': 7, 'yellow': 4, 'red': 2, 'fdw': 23, 'ped': 'walk', 'ped_elapsed': 11, 'ped_truncate': False, 'track_current': False}, [29, 23]), ({'state': 'green', 'elapsed': 7, 'min_green': 14, 'preempt_min_green': 3, 'yellow': 6, 'red': 2, 'fdw': 14, 'ped': 'none', 'ped_elapsed': 1, 'ped_truncate': False, 'track_current': True}, [0, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0])], [({'state': 'yellow', 'elapsed': 5, 'min_green': 14, 'preempt_min_green': 3, 'yellow': 6, 'red': 3, 'fdw': 8, 'ped': 'none', 'ped_elapsed': 7, 'ped_truncate': True, 'track_current': False}, [4, 0]), ({'state': 'green', 'elapsed': 0, 'min_green': 12, 'preempt_min_green': 5, 'yellow': 4, 'red': 1, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [10, 5]), ({'state': 'green', 'elapsed': 5, 'min_green': 12, 'preempt_min_green': 5, 'yellow': 5, 'red': 1, 'fdw': 25, 'ped': 'walk', 'ped_elapsed': 6, 'ped_truncate': True, 'track_current': False}, [6, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 5, 'min_green': 18, 'preempt_min_green': 8, 'yellow': 6, 'red': 3, 'fdw': 19, 'ped': 'fdw', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [19, 10]), ({'state': 'red', 'elapsed': 14, 'min_green': 17, 'preempt_min_green': 9, 'yellow': 5, 'red': 2, 'fdw': 13, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': True, 'track_current': False}, [0, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 16, 'preempt_min_green': 4, 'yellow': 6, 'red': 2, 'fdw': 10, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [11, 3]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8])], [({'state': 'green', 'elapsed': 0, 'min_green': 8, 'preempt_min_green': 9, 'yellow': 3, 'red': 1, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 20, 'ped_truncate': False, 'track_current': False}, [13, 9]), ({'state': 'red', 'elapsed': 14, 'min_green': 8, 'preempt_min_green': 10, 'yellow': 5, 'red': 1, 'fdw': 23, 'ped': 'none', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [0, 0]), ({'state': 'yellow', 'elapsed': 20, 'min_green': 15, 'preempt_min_green': 3, 'yellow': 3, 'red': 2, 'fdw': 17, 'ped': 'none', 'ped_elapsed': 5, 'ped_truncate': False, 'track_current': True}, [2, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 8, 'preempt_min_green': 8, 'yellow': 4, 'red': 1, 'fdw': 22, 'ped': 'walk', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [27, 22]), ({'state': 'yellow', 'elapsed': 10, 'min_green': 11, 'preempt_min_green': 9, 'yellow': 5, 'red': 1, 'fdw': 18, 'ped': 'none', 'ped_elapsed': 17, 'ped_truncate': False, 'track_current': False}, [1, 0]), ({'state': 'green', 'elapsed': 4, 'min_green': 17, 'preempt_min_green': 8, 'yellow': 4, 'red': 1, 'fdw': 11, 'ped': 'walk', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [16, 11]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0])], [({'state': 'green', 'elapsed': 14, 'min_green': 8, 'preempt_min_green': 3, 'yellow': 4, 'red': 2, 'fdw': 8, 'ped': 'fdw', 'ped_elapsed': 16, 'ped_truncate': False, 'track_current': False}, [6, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 3, 'min_green': 17, 'preempt_min_green': 10, 'yellow': 5, 'red': 2, 'fdw': 25, 'ped': 'fdw', 'ped_elapsed': 14, 'ped_truncate': False, 'track_current': False}, [18, 11]), ({'state': 'green', 'elapsed': 1, 'min_green': 10, 'preempt_min_green': 9, 'yellow': 3, 'red': 2, 'fdw': 23, 'ped': 'walk', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': True}, [0, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 14, 'min_green': 13, 'preempt_min_green': 5, 'yellow': 6, 'red': 3, 'fdw': 16, 'ped': 'none', 'ped_elapsed': 18, 'ped_truncate': False, 'track_current': False}, [9, 0]), ({'state': 'green', 'elapsed': 5, 'min_green': 19, 'preempt_min_green': 9, 'yellow': 3, 'red': 1, 'fdw': 19, 'ped': 'fdw', 'ped_elapsed': 16, 'ped_truncate': False, 'track_current': False}, [8, 4]), ({'state': 'green', 'elapsed': 8, 'min_green': 19, 'preempt_min_green': 9, 'yellow': 4, 'red': 2, 'fdw': 13, 'ped': 'walk', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [19, 13])]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| timing oracle 0 | [18, 12] | [14, 8] | Failed |
| timing oracle 1 | [4, 0] | [4, 0] | Passed |
| timing oracle 2 | [14, 7] | [12, 5] | Failed |
| timing oracle 3 | [13, 8] | [12, 7] | Failed |
| timing oracle 4 | [3, 0] | [3, 0] | Passed |
| timing oracle 5 | [10, 6] | [9, 5] | Failed |
| timing oracle 6 | [29, 21] | [22, 14] | Failed |
| timing oracle 7 | [22, 15] | [22, 15] | Passed |
SHA-256 / e84edb3c3e86d30a5dbc283a40ab7756b9c9ba6108732311e19aef0a872841f7
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(x):
st, el = x['state'], x['elapsed']
y, r, f = x['yellow'], x['red'], x['fdw']
if st == 'green' and x['track_current']:
return [0, 0]
if st == 'red':
return [max(0, r - el), 0]
if st == 'yellow':
return [max(0, y - el) + r, 0]
ped = 0
if x['ped'] == 'walk':
ped = 0 if x['ped_truncate'] else f
elif x['ped'] == 'fdw':
ped = 0 if x['ped_truncate'] else max(0, f - x['ped_elapsed'])
hold = ped or max(0, x['preempt_min_green'] - el)
return [hold + y + r, hold]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 4, 'min_green': 20, 'preempt_min_green': 9, 'yellow': 5, 'red': 2, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 12, 'ped_truncate': False, 'track_current': False}, [12, 5]), ({'state': 'green', 'elapsed': 4, 'min_green': 19, 'preempt_min_green': 5, 'yellow': 3, 'red': 2, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 17, 'ped_truncate': False, 'track_current': False}, [12, 7]), ({'state': 'yellow', 'elapsed': 19, 'min_green': 11, 'preempt_min_green': 3, 'yellow': 5, 'red': 3, 'fdw': 20, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [3, 0]), ({'state': 'green', 'elapsed': 2, 'min_green': 17, 'preempt_min_green': 7, 'yellow': 3, 'red': 1, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [9, 5]), ({'state': 'green', 'elapsed': 2, 'min_green': 9, 'preempt_min_green': 9, 'yellow': 5, 'red': 3, 'fdw': 14, 'ped': 'walk', 'ped_elapsed': 5, 'ped_truncate': False, 'track_current': False}, [22, 14]), ({'state': 'green', 'elapsed': 11, 'min_green': 18, 'preempt_min_green': 8, 'yellow': 5, 'red': 2, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [22, 15])], [({'state': 'yellow', 'elapsed': 17, 'min_green': 10, 'preempt_min_green': 7, 'yellow': 3, 'red': 3, 'fdw': 20, 'ped': 'none', 'ped_elapsed': 2, 'ped_truncate': False, 'track_current': True}, [3, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 0, 'min_green': 10, 'preempt_min_green': 9, 'yellow': 5, 'red': 3, 'fdw': 20, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [17, 9]), ({'state': 'green', 'elapsed': 6, 'min_green': 17, 'preempt_min_green': 7, 'yellow': 5, 'red': 2, 'fdw': 20, 'ped': 'fdw', 'ped_elapsed': 3, 'ped_truncate': False, 'track_current': False}, [24, 17]), ({'state': 'green', 'elapsed': 4, 'min_green': 16, 'preempt_min_green': 8, 'yellow': 5, 'red': 1, 'fdw': 8, 'ped': 'walk', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 7, 'min_green': 19, 'preempt_min_green': 7, 'yellow': 4, 'red': 2, 'fdw': 23, 'ped': 'walk', 'ped_elapsed': 11, 'ped_truncate': False, 'track_current': False}, [29, 23]), ({'state': 'green', 'elapsed': 7, 'min_green': 14, 'preempt_min_green': 3, 'yellow': 6, 'red': 2, 'fdw': 14, 'ped': 'none', 'ped_elapsed': 1, 'ped_truncate': False, 'track_current': True}, [0, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0])], [({'state': 'yellow', 'elapsed': 5, 'min_green': 14, 'preempt_min_green': 3, 'yellow': 6, 'red': 3, 'fdw': 8, 'ped': 'none', 'ped_elapsed': 7, 'ped_truncate': True, 'track_current': False}, [4, 0]), ({'state': 'green', 'elapsed': 0, 'min_green': 12, 'preempt_min_green': 5, 'yellow': 4, 'red': 1, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [10, 5]), ({'state': 'green', 'elapsed': 5, 'min_green': 12, 'preempt_min_green': 5, 'yellow': 5, 'red': 1, 'fdw': 25, 'ped': 'walk', 'ped_elapsed': 6, 'ped_truncate': True, 'track_current': False}, [6, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 5, 'min_green': 18, 'preempt_min_green': 8, 'yellow': 6, 'red': 3, 'fdw': 19, 'ped': 'fdw', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [19, 10]), ({'state': 'red', 'elapsed': 14, 'min_green': 17, 'preempt_min_green': 9, 'yellow': 5, 'red': 2, 'fdw': 13, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': True, 'track_current': False}, [0, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 16, 'preempt_min_green': 4, 'yellow': 6, 'red': 2, 'fdw': 10, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [11, 3]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8])], [({'state': 'green', 'elapsed': 0, 'min_green': 8, 'preempt_min_green': 9, 'yellow': 3, 'red': 1, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 20, 'ped_truncate': False, 'track_current': False}, [13, 9]), ({'state': 'red', 'elapsed': 14, 'min_green': 8, 'preempt_min_green': 10, 'yellow': 5, 'red': 1, 'fdw': 23, 'ped': 'none', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [0, 0]), ({'state': 'yellow', 'elapsed': 20, 'min_green': 15, 'preempt_min_green': 3, 'yellow': 3, 'red': 2, 'fdw': 17, 'ped': 'none', 'ped_elapsed': 5, 'ped_truncate': False, 'track_current': True}, [2, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 8, 'preempt_min_green': 8, 'yellow': 4, 'red': 1, 'fdw': 22, 'ped': 'walk', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [27, 22]), ({'state': 'yellow', 'elapsed': 10, 'min_green': 11, 'preempt_min_green': 9, 'yellow': 5, 'red': 1, 'fdw': 18, 'ped': 'none', 'ped_elapsed': 17, 'ped_truncate': False, 'track_current': False}, [1, 0]), ({'state': 'green', 'elapsed': 4, 'min_green': 17, 'preempt_min_green': 8, 'yellow': 4, 'red': 1, 'fdw': 11, 'ped': 'walk', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [16, 11]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0])], [({'state': 'green', 'elapsed': 14, 'min_green': 8, 'preempt_min_green': 3, 'yellow': 4, 'red': 2, 'fdw': 8, 'ped': 'fdw', 'ped_elapsed': 16, 'ped_truncate': False, 'track_current': False}, [6, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 3, 'min_green': 17, 'preempt_min_green': 10, 'yellow': 5, 'red': 2, 'fdw': 25, 'ped': 'fdw', 'ped_elapsed': 14, 'ped_truncate': False, 'track_current': False}, [18, 11]), ({'state': 'green', 'elapsed': 1, 'min_green': 10, 'preempt_min_green': 9, 'yellow': 3, 'red': 2, 'fdw': 23, 'ped': 'walk', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': True}, [0, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 14, 'min_green': 13, 'preempt_min_green': 5, 'yellow': 6, 'red': 3, 'fdw': 16, 'ped': 'none', 'ped_elapsed': 18, 'ped_truncate': False, 'track_current': False}, [9, 0]), ({'state': 'green', 'elapsed': 5, 'min_green': 19, 'preempt_min_green': 9, 'yellow': 3, 'red': 1, 'fdw': 19, 'ped': 'fdw', 'ped_elapsed': 16, 'ped_truncate': False, 'track_current': False}, [8, 4]), ({'state': 'green', 'elapsed': 8, 'min_green': 19, 'preempt_min_green': 9, 'yellow': 4, 'red': 2, 'fdw': 13, 'ped': 'walk', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [19, 13])]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| timing oracle 0 | [14, 8] | [14, 8] | Passed |
| timing oracle 1 | [4, 0] | [4, 0] | Passed |
| timing oracle 2 | [9, 2] | [12, 5] | Failed |
| timing oracle 3 | [12, 7] | [12, 7] | Passed |
| timing oracle 4 | [3, 0] | [3, 0] | Passed |
| timing oracle 5 | [5, 1] | [9, 5] | Failed |
| timing oracle 6 | [22, 14] | [22, 14] | Passed |
| timing oracle 7 | [22, 15] | [22, 15] | Passed |
SHA-256 / 736f0e334bcc73ecdf6bcfdc667378c3b4cc20c60cf340472fde3c392945cdcb
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(x):
st, el = x['state'], x['elapsed']
y, r, f = x['yellow'], x['red'], x['fdw']
if st == 'green' and x['track_current']:
return [0, 0]
if st == 'red':
return [max(0, r - el), 0]
if st == 'yellow':
return [max(0, y - el) + r, 0]
ped = 0
if x['ped'] == 'walk':
ped = 0 if x['ped_truncate'] else f
elif x['ped'] == 'fdw':
ped = 0 if x['ped_truncate'] else max(0, f - x['ped_elapsed'])
hold = max(ped, max(0, x['preempt_min_green'] - el))
return [hold + y + r, hold]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 4, 'min_green': 20, 'preempt_min_green': 9, 'yellow': 5, 'red': 2, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 12, 'ped_truncate': False, 'track_current': False}, [12, 5]), ({'state': 'green', 'elapsed': 4, 'min_green': 19, 'preempt_min_green': 5, 'yellow': 3, 'red': 2, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 17, 'ped_truncate': False, 'track_current': False}, [12, 7]), ({'state': 'yellow', 'elapsed': 19, 'min_green': 11, 'preempt_min_green': 3, 'yellow': 5, 'red': 3, 'fdw': 20, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [3, 0]), ({'state': 'green', 'elapsed': 2, 'min_green': 17, 'preempt_min_green': 7, 'yellow': 3, 'red': 1, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [9, 5]), ({'state': 'green', 'elapsed': 2, 'min_green': 9, 'preempt_min_green': 9, 'yellow': 5, 'red': 3, 'fdw': 14, 'ped': 'walk', 'ped_elapsed': 5, 'ped_truncate': False, 'track_current': False}, [22, 14]), ({'state': 'green', 'elapsed': 11, 'min_green': 18, 'preempt_min_green': 8, 'yellow': 5, 'red': 2, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [22, 15])], [({'state': 'yellow', 'elapsed': 17, 'min_green': 10, 'preempt_min_green': 7, 'yellow': 3, 'red': 3, 'fdw': 20, 'ped': 'none', 'ped_elapsed': 2, 'ped_truncate': False, 'track_current': True}, [3, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 0, 'min_green': 10, 'preempt_min_green': 9, 'yellow': 5, 'red': 3, 'fdw': 20, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [17, 9]), ({'state': 'green', 'elapsed': 6, 'min_green': 17, 'preempt_min_green': 7, 'yellow': 5, 'red': 2, 'fdw': 20, 'ped': 'fdw', 'ped_elapsed': 3, 'ped_truncate': False, 'track_current': False}, [24, 17]), ({'state': 'green', 'elapsed': 4, 'min_green': 16, 'preempt_min_green': 8, 'yellow': 5, 'red': 1, 'fdw': 8, 'ped': 'walk', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 7, 'min_green': 19, 'preempt_min_green': 7, 'yellow': 4, 'red': 2, 'fdw': 23, 'ped': 'walk', 'ped_elapsed': 11, 'ped_truncate': False, 'track_current': False}, [29, 23]), ({'state': 'green', 'elapsed': 7, 'min_green': 14, 'preempt_min_green': 3, 'yellow': 6, 'red': 2, 'fdw': 14, 'ped': 'none', 'ped_elapsed': 1, 'ped_truncate': False, 'track_current': True}, [0, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0])], [({'state': 'yellow', 'elapsed': 5, 'min_green': 14, 'preempt_min_green': 3, 'yellow': 6, 'red': 3, 'fdw': 8, 'ped': 'none', 'ped_elapsed': 7, 'ped_truncate': True, 'track_current': False}, [4, 0]), ({'state': 'green', 'elapsed': 0, 'min_green': 12, 'preempt_min_green': 5, 'yellow': 4, 'red': 1, 'fdw': 14, 'ped': 'fdw', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': False}, [10, 5]), ({'state': 'green', 'elapsed': 5, 'min_green': 12, 'preempt_min_green': 5, 'yellow': 5, 'red': 1, 'fdw': 25, 'ped': 'walk', 'ped_elapsed': 6, 'ped_truncate': True, 'track_current': False}, [6, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 5, 'min_green': 18, 'preempt_min_green': 8, 'yellow': 6, 'red': 3, 'fdw': 19, 'ped': 'fdw', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [19, 10]), ({'state': 'red', 'elapsed': 14, 'min_green': 17, 'preempt_min_green': 9, 'yellow': 5, 'red': 2, 'fdw': 13, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': True, 'track_current': False}, [0, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 16, 'preempt_min_green': 4, 'yellow': 6, 'red': 2, 'fdw': 10, 'ped': 'none', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [11, 3]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8])], [({'state': 'green', 'elapsed': 0, 'min_green': 8, 'preempt_min_green': 9, 'yellow': 3, 'red': 1, 'fdw': 24, 'ped': 'fdw', 'ped_elapsed': 20, 'ped_truncate': False, 'track_current': False}, [13, 9]), ({'state': 'red', 'elapsed': 14, 'min_green': 8, 'preempt_min_green': 10, 'yellow': 5, 'red': 1, 'fdw': 23, 'ped': 'none', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [0, 0]), ({'state': 'yellow', 'elapsed': 20, 'min_green': 15, 'preempt_min_green': 3, 'yellow': 3, 'red': 2, 'fdw': 17, 'ped': 'none', 'ped_elapsed': 5, 'ped_truncate': False, 'track_current': True}, [2, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 8, 'preempt_min_green': 8, 'yellow': 4, 'red': 1, 'fdw': 22, 'ped': 'walk', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [27, 22]), ({'state': 'yellow', 'elapsed': 10, 'min_green': 11, 'preempt_min_green': 9, 'yellow': 5, 'red': 1, 'fdw': 18, 'ped': 'none', 'ped_elapsed': 17, 'ped_truncate': False, 'track_current': False}, [1, 0]), ({'state': 'green', 'elapsed': 4, 'min_green': 17, 'preempt_min_green': 8, 'yellow': 4, 'red': 1, 'fdw': 11, 'ped': 'walk', 'ped_elapsed': 8, 'ped_truncate': False, 'track_current': False}, [16, 11]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0])], [({'state': 'green', 'elapsed': 14, 'min_green': 8, 'preempt_min_green': 3, 'yellow': 4, 'red': 2, 'fdw': 8, 'ped': 'fdw', 'ped_elapsed': 16, 'ped_truncate': False, 'track_current': False}, [6, 0]), ({'state': 'green', 'elapsed': 1, 'min_green': 15, 'preempt_min_green': 5, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'fdw', 'ped_elapsed': 4, 'ped_truncate': False, 'track_current': False}, [14, 8]), ({'state': 'green', 'elapsed': 3, 'min_green': 17, 'preempt_min_green': 10, 'yellow': 5, 'red': 2, 'fdw': 25, 'ped': 'fdw', 'ped_elapsed': 14, 'ped_truncate': False, 'track_current': False}, [18, 11]), ({'state': 'green', 'elapsed': 1, 'min_green': 10, 'preempt_min_green': 9, 'yellow': 3, 'red': 2, 'fdw': 23, 'ped': 'walk', 'ped_elapsed': 13, 'ped_truncate': False, 'track_current': True}, [0, 0]), ({'state': 'yellow', 'elapsed': 2, 'min_green': 10, 'preempt_min_green': 4, 'yellow': 4, 'red': 2, 'fdw': 12, 'ped': 'none', 'ped_elapsed': 0, 'ped_truncate': False, 'track_current': True}, [4, 0]), ({'state': 'green', 'elapsed': 14, 'min_green': 13, 'preempt_min_green': 5, 'yellow': 6, 'red': 3, 'fdw': 16, 'ped': 'none', 'ped_elapsed': 18, 'ped_truncate': False, 'track_current': False}, [9, 0]), ({'state': 'green', 'elapsed': 5, 'min_green': 19, 'preempt_min_green': 9, 'yellow': 3, 'red': 1, 'fdw': 19, 'ped': 'fdw', 'ped_elapsed': 16, 'ped_truncate': False, 'track_current': False}, [8, 4]), ({'state': 'green', 'elapsed': 8, 'min_green': 19, 'preempt_min_green': 9, 'yellow': 4, 'red': 2, 'fdw': 13, 'ped': 'walk', 'ped_elapsed': 9, 'ped_truncate': False, 'track_current': False}, [19, 13])]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| timing oracle 0 | [14, 8] | [14, 8] | Passed |
| timing oracle 1 | [4, 0] | [4, 0] | Passed |
| timing oracle 2 | [12, 5] | [12, 5] | Passed |
| timing oracle 3 | [12, 7] | [12, 7] | Passed |
| timing oracle 4 | [3, 0] | [3, 0] | Passed |
| timing oracle 5 | [9, 5] | [9, 5] | Passed |
| timing oracle 6 | [22, 14] | [22, 14] | Passed |
| timing oracle 7 | [22, 15] | [22, 15] | Passed |
SHA-256 / c9e689db3f884015b33a856c8d9941f66e469bf906fb0621d4f01c4ae31e7631
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 2026-09-29T14:47:59.845334+00:00.
Case digest / fa60033b686d3212800e38dd29ddf9c18c734882302cd646b94a67288ea4e1e2