I am the owner of a 2016 Spark EV, and the driver was my family member. The vehicle was charged and had a remaining driving range of 51 miles when the vehicle suddenly shut down on a major city road without any prior warning or symptoms of a problem. The vehicle did not restart immediately, and other drivers behind had to push the vehicle to the side of the road. The driver experienced the shutdown of the vehicle while driving again on another day. Since the sudden shutdown of the propulsion power while driving happened without any prior warning light, message, or symptom, the incident could put the safety of the driver and others at risk, especially if the shutdown happened at a higher speed on a highway. Failure of a specific component or system has not been identified, but the vehicle is available for inspection upon request. The service department of a Chevrolet dealer initially provided an estimated diagnostic fee of $170, but the service department raised the diagnostic fee by double upon check-in when the vehicle was brought in on the scheduled appointment. I canceled the appointment in frustration.