My friend had his first seizure in his mid 30s behind the wheel of his car.
Nothing before at all.
Luckily dh was in the passenger seat and another friend behind. Dh stopped the car with his hands in the foot brake and our friend steers from the back seat to ensure they didn't crash into houses or a wall.
Although he was conscious and talking after they came to a stop it was clear to those who,knew him things weren't right. He has no memory of this time now, or of before it,
The hospital discharged our friend that day, after tests. They didn't tell him not to drive or anything and infact he turned up at our house for car keys. Fortunately his partner prevented him from driving and made him go to his go the next day. It was there that's more tests went ahead, and he had to surrender his license.
He had 2 more seizures before being put on medication, one more whilst driving. Again fortunately no one was hurt.
It's now been well over a decade and he has had nothing since. He got his licence back 12 months after the last seizure and has driven safely since.
15 minutes later, in that first incident, he'd have been alone in the car in a motorway.
An hour later he'd have been on the motorway with his young child in the back of the car.
The day after, at the same time, the road where it happened would have been busy, lots of school children around, buses and cars doing morning school/work commutes, etc.
It was just luck no one was hurt (as well as dh/friend's actions) and it was bad luck he had a seizure out of nowhere.