FA-12206 / Navigation route constraints / Open access

A vehicle is admitted without sufficient surveyed clearance · case 01

A vehicle is admitted without sufficient surveyed clearance in the controlled route-policy fixture.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Only physical height is compared, omitting the specified safety margin and treating unknown clearance as safe.

THE FAILURE

Only physical height is compared, omitting the specified safety margin and treating unknown clearance as safe.

Unsuccessful approach: A strict comparison rejects exact equality even though the modeled threshold is inclusive.

Case contract

All dimensions are integer centimeters. Unknown clearance is None and rejects travel; equality with height plus margin permits travel.

Why this case matters

Navigation policies depend on road context that a shortest-path cost alone does not encode.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(height, margin, clearance):
    return clearance is None or height <= clearance
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
h = 200 + N
check('unknown survey', solve(h,10,None), False)
check('margin omitted', solve(h,10,h+5), False)
check('exact threshold', solve(h,10,h+10), True)
check('above threshold', solve(h,10,h+11), True)
check('physical collision', solve(h,0,h-1), False)
check('zero margin equality', solve(h,0,h), True)
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
unknown survey	`True`	`False`	Failed
margin omitted	`True`	`False`	Failed
exact threshold	`True`	`True`	Passed
above threshold	`True`	`True`	Passed
physical collision	`False`	`False`	Passed
zero margin equality	`True`	`True`	Passed

SHA-256 / 60380caa8ff3e114a8ab2c6567f4608a43c8928c72419243c064b569ffda2142

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(height, margin, clearance):
    return clearance is not None and height + margin < clearance
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
h = 200 + N
check('unknown survey', solve(h,10,None), False)
check('margin omitted', solve(h,10,h+5), False)
check('exact threshold', solve(h,10,h+10), True)
check('above threshold', solve(h,10,h+11), True)
check('physical collision', solve(h,0,h-1), False)
check('zero margin equality', solve(h,0,h), True)
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
unknown survey	`False`	`False`	Passed
margin omitted	`False`	`False`	Passed
exact threshold	`False`	`True`	Failed
above threshold	`True`	`True`	Passed
physical collision	`False`	`False`	Passed
zero margin equality	`False`	`True`	Failed

SHA-256 / cb7ff8fa0d0a28a97ee6ec66e12d1b23c6666d557b9af87a079b3972db065515

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 6 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.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

Simplified deterministic offline policy model; not a production router or authoritative road guidance. 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 2026-09-29T14:38:54.880168+00:00.

Case digest / 5d8397961f64c3760d0c0ba4a90876de93bd68ba6b213a75c86897cd933aadd7