Last week, a California man caused a news sensation and a large traffic jam when his Prius went 90+ miles per hour on a California highway and only stopped when a police officer used his cruiser to slow the thing down. The car was tested over the weekend, and engineers were unable to reproduce the problem. Naturally, the news media is going with the claims that the man driving the car must have been lying. Gotta get those viewers!
I'm no automotive engineer, but I think we've all seen our share of problems that wound up being "unreproducible". Think of all the things it could be:
- A race condition in software and/or hardware
- A deadlock in software (does hardware have deadlocks?)
- User error: the man didn't follow a procedure that could have stopped the car
- User error: the man maliciously managed to get his break lights to turn on without actually attempting to break
- Incorrect entry conditions: the problem only happens after the car has been driven for some period of time
- Incorrect entry conditions: the problem only occurs when the car is at a certain speed and some other event (momentary breaking, gear shift, acceleration) also occurs
- Incorrect entry conditions: the problem only happens when the seat is in a certain position (thus putting the angle of pedal pressure at some key spot)
I'm sure there are many many more possible explanations. Like many unreproducible issues, this one may never be definitively solved. It's an interesting exercise, though, to come up with ideas. What other possibilities can you think of?