Surveillance footage shows a passenger jump into action to steer a bus to safety and call dispatch, after another passenger noticed the driver in distress.
The Mountain Metropolitan Transit (MMT) told BBC the driver suffered a medical emergency and collapsed, at about 07:45 on 14 October in Colorado Springs.
Despite the efforts of emergency responders, the driver died. There were only two passengers on board the bus at the time of the incident, MMT said.