This is hopefully not important for anyone. It is simply a public record of what happened in case it is useful because of a problem.
In Berkeley, CA in October we rented a Budget rental car numbered 47088182, a gray Hyundai Elantra with Washington plates BAZ7021. While driving on the highway, we were in a dark shadow behind a hill so I turned on the headlights. Immediately all electrical systems stopped functioning: dash lights, AC, power steering, and I think even the engine stopped. The car shuddered, I think from the cams suddenly stopping. Fortunately, though this was a curvy mountain road into Santa Cruz, this particular section was straight otherwise I may have been unable to stay in my lane. After 3-5 seconds, electrical power returned - the engine, steering, lights, AC all came back on as if nothing had happened.
There was no Budget available in Santa Cruz so I drove the car later that day to the Oakland Airport as planned to return the car. I reported the problem to the person who collects the return cars in the lot and he said that he would make sure it was checked by a mechanic before it went out again. I later called Budget to try and get my rental cost refunded (the least they could do for putting my family in serious danger) but they only gave me 50% back, and only after talking to a "manager". Customer service claimed to be totally unaware of this problem with the car, so I'm not sure if the person collecting the car a month prior had properly reported the issue.
So if this car causes someone to get into an accident I just want to make it clear that Budget was informed of this problem on October 23, 2017 and again on November 16, 2017.