A dual air vehicle suffers a complete rupture in the primary service circuit. The low-air warning comes on, but secondary reservoir pressure remains. What is the safest interpretation?

1. The vehicle has full normal braking and may continue the trip
2. The driver may still make a controlled stop with reduced braking and must not continue until repaired
3. The spring parking brakes must be caged before stopping
4. The reservoir gauges are irrelevant because dual systems do not use gauges