Vehicle Plate

Purpose

Use the vehicle_plate detector for Czech vehicle registration plates (SPZ / license plates).

This detector reports accuracy above 95% and supports both older plate patterns and newer regional-code variants.

It also extracts a region hint for the new-style format when the prefix matches the built-in regional map.

Detector Name

vehicle_plate

Supported Formats

• Old format: 2-3 letters + 3-4 digits
• New format: regional code variants such as 1A2 3456

Examples:

• 1A2 3456
• ABC 1234

Validation Logic

The detector evaluates two families of regex patterns.

New Format

• First block: regional code plus letters and digits
• Second block: 4-5 alphanumeric characters

Old Format

• 3 letters
• Space
• 3-4 digits

Plate Rules

After pattern matching, FastPII applies these checks:

1. Reject any plate containing Q.
2. For new plates, require total length without spaces between 6 and 8.
3. For old plates, require total length without spaces between 6 and 7.
4. Use the leading prefix to look up a known region for new-format plates.

There is no checksum algorithm for this detector.

Python Examples

Validate a vehicle plate

from fastpii import PrivacyGuard

guard = PrivacyGuard(regions=["cz"])
result = guard.validate("1A2 3456", "vehicle_plate")

print(result.is_valid)
print(result.metadata)

Detect in text

from fastpii import PrivacyGuard

guard = PrivacyGuard(regions=["cz"])
result = guard.detect("SPZ: 1A2 3456", detector_names=["vehicle_plate"])

for finding in result.findings:
    print(finding.value, finding.metadata)

Expected Metadata

This detector can return:

• plate
• format
• region

Old-format findings include plate and format, while new-format findings also include a region hint from the prefix map.

Example Output

{
    "plate": "1A2 3456",
    "format": "new",
    "region": "Praha",
}

Limitations

• Region metadata is based on the detector's internal prefix table.
• The detector validates structure, not registration authority records.
• Old-format plates do not expose the same regional metadata as new-format plates.

Notes

Verified validation example from the codebase:

guard.validate("1A2 3456", "vehicle_plate")