On XXX, I was the sole passenger in a driverless Waymo (XXX) in [XXX]. Pickup: Chase Field ~4:14 PM. At ~4:25 PM on [XXX], a multi-lane urban arterial, the automated driving system decelerated the vehicle without cause to ~10 mph and held that speed in the number one (leftmost) lane. There was no obstacle, pedestrian, emergency vehicle, work zone, signal, or traffic condition to explain it. Traffic passed at normal speed in adjacent lanes. The system merged to the center lane, then returned to the number one lane, still at ~10 mph. The vehicle was a slow-moving obstruction in a live travel lane. There was no steering wheel, no pedal, no human driver. I could not accelerate, pull over, or exit the lane. My exposure to a rear-end collision was created solely by the ADS and could be ended only by the ADS, which was not ending it. I called Waymo rider support. The vehicle remained at ~10 mph. About 30 seconds in, a remote agent overrode the system and restored normal speed. Key finding: the malfunction did not self-correct. The vehicle did not detect the anomaly, resolve it, or degrade to a safe state. It operated hazardously until a remote human took control. The system’s own safety architecture did not catch it. A human did, only because I called. Waymo confirmed in writing that it verified the event as described, then declined to provide root cause, telemetry, or any investigative outcome absent legal process. I request NHTSA determine: (1) whether this was reported under the Standing General Order for ADS vehicles, or deemed below threshold and on what basis; (2) whether unexplained deceleration, sustained low-speed travel in live lanes, or failure-to-self-correct events have been reported for this fleet in the Phoenix ODD; (3) whether an ADS that cannot correct its own hazardous speed loss without remote human rescue meets any reasonable safety expectation for driverless operation on public arterials. Please contact me. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)