NHTSA Complaint #11711269 — 2015 MAZDA MAZDA3

Description On 12-15-2025, in 18°F weather, the vehicle was parked on a residential sloped driveway with the manual parking brake fully engaged. While the driver was outside the vehicle, the parking brake system failed to hold the car’s weight. The vehicle rolled backward, crashed through a wooden railing, teetering on a 4-foot retaining wall, and came to rest over a culvert. Two young children were inside the vehicle at the time of the failure. Component Failure & Availability: The manual parking brake system failed to provide sufficient holding force to secure the vehicle. The rear brake calipers are currently available for inspection. Safety Risk: The safety of the two children inside the vehicle was put at extreme risk due to the unexpected movement of the car. This failure matches the exact conditions and consequences described in Safety Recall 1217F (NHTSA Campaign 17V-393), which states that "unexpected movement of the vehicle if parked on a slope" increases the risk of a collision. Reproducibility & Confirmation: The failure occurred under the specific environmental triggers (cold temperature and slope) identified in the manufacturer's own safety recall documentation. However, the manufacturer has officially refused to authorize the internal teardown of the actuator shafts—the only diagnostic method capable of verifying the rust and sliding resistance that causes this loss of holding force. Inspections: The vehicle has been visually inspected by an authorized dealership and insurance representatives. The manufacturer has declined the necessary internal mechanical diagnostics to verify the internal defect. Warning Symptoms: There were no warning lamps, messages, or symptoms prior to the failure. The parking brake felt fully engaged at the time the vehicle was parked.