Yeah, Matrix.
Do you drive your car in busy traffic having doubts about everything you see around you is an illusion? Or do you trust seeing a red light and reacting to is by stopping your vehicle?
It's easy to sit on the couch and be stoned (am I really stoned?) and ponder if's and doubts. But when your life is on the line, like driving in traffic, that kind of thinking is abandonded fast.
Well, your example of traffic could also apply for a certain subvariant of a Boltzmann Brain existence.
So no, just because you die, doesn't mean that you are in a real world.
So here it goes and since I know how assumptions work I will try to state them all.
There is no way to know if you are a Boltzmann Brain or not, because if you are, your experiences are caused by you being a Boltzmann Brain.
All scientific claims on whether these Brains are speculative or not all rest on different assumptions about how the universe work.
So here is what I assume that you need to test. You have to test if your experience of e.g. a car means that the car in itself is a car and not a simulation of a car.
You have to test that, because since you use critical thinking you are not allowed to claim something without testing it.
So here are the actual assumptions.
You could be a Boltzmann Brain.
You could be a simulation on a computer, which came into being like a Boltzmann brain.
You could be turned off as a simulation by by the main operating system of the computer, if you "break the rules". I.e. traffic as per your example.
So please give evidence that you are real and not a simulation on a Boltzmann Brain computer. Remember evidence. Not that it doesn't make sense to you, because that is the same for both cases. Evidence, factual evidence.
BTW if you can that, give evidence, then you are the first human in recorded history to do that.