If you kept such things inside the car it would be much easier to access them. As already stated, in a pocket in one of the doors, in the glove box, in pockets hanging from the front seats.
A triangle can be propped up in your rear window, & front, too, if you have a spare!
Blankets are always handy and can be rolled up to use as cushions on the back seat, or spread out to sit on them!
Hi vis are DEFINITELY great items, along with a little first aid kit!
And those blankets emergency people carry that are silver, they pack away neatly into small spaces!
Things like these can fit under the front seats, if packed right!
As they say, better safe than sorry!!
I'm glad you are safe, @fancythat, and that your daughter was quick thinking, @Oopsadaisy1.